Shawn Smith v. United States , 180 A.3d 45 ( 2018 )


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  •                                 District of Columbia
    Court of Appeals
    No. 15-CF-677
    March 8, 2018
    SHAWN SMITH,
    Appellant,
    v.                                                 CF2-8362-14
    UNITED STATES,
    Appellee.
    On Appeal from the Superior Court of the District of Columbia
    Before THOMPSON and MCLEESE, Associate Judges, and FERREN,* Senior Judge.
    JUDGMENT
    This case came to be heard on the transcript of record, the briefs filed, and
    was argued by counsel. On consideration whereof, and as set forth in the opinion filed
    this date, it is now hereby
    ORDERED and ADJUDGED that the trial court’s judgment is affirmed.
    For the Court:
    Dated: March 8, 2018.
    Opinion by Senior Judge John M. Ferren.
    Opinion concurring in the judgment by Associate Judge Phyllis D. Thompson.
    Dissenting opinion by Associate Judge Roy McLeese.
    *
    Senior Judge Belson was originally assigned to this case. Following his
    retirement on July 24, 2017, Senior Judge Ferren was assigned to take his place on
    the division.
    Notice: This opinion is subject to formal revision before publication in the
    Atlantic and Maryland Reporters. Users are requested to notify the Clerk of the
    Court of any formal errors so that corrections may be made before the bound
    volumes go to press.
    DISTRICT OF COLUMBIA COURT OF APPEALS
    No. 15-CF-677
    SHAWN SMITH, APPELLANT,
    03/08/2018
    V.
    UNITED STATES, APPELLEE.
    Appeal from the Superior Court
    of the District of Columbia
    (CF2-8362-14)
    (Hon. Anita Josey-Herring, Trial Judge)
    (Argued January 24, 2017                                  Decided March 8, 2018)
    William Collins, Public Defender Service, with whom Samia Fam, Jonathan
    Anderson, and Jaclyn Frankfurt, Public Defender Service, were on the brief, for
    appellant.
    Peter S. Smith, Assistant United States Attorney, with whom Channing D.
    Phillips, United States Attorney at the time the briefs were filed, and Elizabeth
    Trosman and Laura Crane, Assistant United States Attorneys, were on the brief,
    for appellee.
    Before THOMPSON and MCLEESE, Associate Judges, and FERREN,* Senior
    Judge.
    *
    Senior Judge Belson was originally assigned to this case. Following his
    retirement on July 24, 2017, Senior Judge Ferren was assigned to take his place on
    the division.
    2
    Opinion for the court by Senior Judge FERREN.
    Opinion concurring in the judgment by Associate Judge THOMPSON, at page
    53.
    Dissenting opinion by Associate Judge MCLEESE, at page 57.
    FERREN, Senior Judge: Appellant, Shawn Smith, was convicted of carrying
    a pistol outside of his home or place of business,1 unlawful possession of a firearm
    by a former felon,2 possession of an unregistered firearm,3 and possession of a
    large capacity ammunition feeding device.4 He appeals his convictions, arguing
    for reversal on several grounds:
    (1) The trial court violated his Sixth Amendment right to cross-examine the
    arresting police officer on a theory of “corruption bias.”
    (2) The trial court erred by precluding impeachment of the officer after he
    “falsely and repeatedly” testified that he had been “attacked and acted in self-
    defense” when striking a crime scene observer.
    1
    
    D.C. Code § 22-4504
     (a)(2) (2001).
    2
    
    D.C. Code § 22-4503
     (a)(1) (2001).
    3
    
    D.C. Code § 7-2502.01
     (a) (2001).
    4
    
    D.C. Code § 7-2506.1
     (b) (2001).
    3
    (3) The government‟s delayed and incomplete mid-trial disclosure of the
    officer‟s pending excessive force investigation in another case violated appellant‟s
    due process rights under Brady v. Maryland,5 warranting reversal.
    For the reasons that follow, we affirm.
    I. Facts and Proceedings
    A. Events at Issue
    According to the government‟s evidence, at approximately 1:00 a.m. on May
    11, 2014, officers of the Seventh District Metropolitan Police Department
    (“MPD”) observed a dozen or so individuals walking along 13th Street, S.E.
    toward Alabama Avenue. As Officers Damien Williams and Terry Couch left their
    vehicle “to see what was going on,” a man later identified as appellant Smith
    turned and began to run down the street into an alley near Savannah Street, S.E.
    The officers ran after Smith, who was holding his waistband while running. As
    Smith passed a wooden fence enclosing a yard near the alley, he pulled what
    “clearly” appeared to be a black semiautomatic handgun from his waistband and
    5
    
    373 U.S. 83
     (1963).
    4
    tossed it over the wooden fence into the yard. At the time Smith discarded the
    handgun, Officer Couch was approximately five to six feet behind him, followed
    closely by Officer Williams. Both officers described the area as “dimly lit” with
    streetlights.
    As Officer Couch continued to pursue Smith, Officer Williams stopped to
    search for the discarded handgun. Upon entering the yard, Williams located a
    handgun lying in the grass approximately six feet from the fence. He observed a
    small indentation in the ground where the handgun appeared to have landed, as
    well as dirt on the handgun‟s barrel. The handgun was also dry compared to the
    surrounding area, which was wet from recent rain. Rather than contact crime-
    scene personnel to process the area, Officer Williams photographed the handgun
    using his cellular phone. He then put on gloves to recover it, placed it in an
    evidence bag, and transported it to the police station. The parties stipulated that no
    fingerprints were discovered on the handgun and that DNA testing was
    inconclusive.
    While Officer Williams was recovering the handgun, Officer Couch
    continued to pursue Smith on foot and caught up to him about a block from where
    the handgun was discovered. Officer Couch explained that as they crossed over
    5
    13th Street, S.E. in a sprint, Smith “tripped, fell, [or] stopped,” causing them both
    to fall. The officer then handcuffed Smith and transported him to the hospital.
    Eventually, Smith was charged.
    B. The Trial
    Before swearing in the jury on December 17, 2014, the trial judge asked the
    parties whether there were any preliminary matters that warranted the court‟s
    attention. Both responded that there were none, whereupon each made opening
    statements to the jury. The government then requested a bench conference. At the
    bench, the government disclosed that its key witness, Officer Williams, was under
    investigation by the United States Attorney‟s Office for using “excessive force”
    against a bystander, Antwann Barkley, in an unrelated incident (“Barkley
    incident”) that took place on December 1, 2014, almost seven months after the
    incident at issue here. The judge ordered the government to present its second
    witness (Officer Couch) first and held over discussion of the issues derived from
    the government‟s delayed disclosure until after Couch had testified. During a
    break in testimony, the prosecutor indicated that she had learned of the pending
    investigation a day or two earlier; that there was “no report” because the
    investigation was still “open”; and that there were “no documents” related to the
    investigation.
    6
    After a second break in Couch‟s testimony, however, the prosecutor
    discovered a preliminary Internal Affairs Division (“IAD”) report about the
    pending investigation, which she produced.        It was dated eight days earlier,
    December 9, 2014, based on a referral to the U.S. Attorney‟s office on the day it
    happened, December 1. This “preliminary” document (hereafter the “IAD report”)
    summarized the Barkley incident, as follows: On December 1, 2014, Officer
    Williams responded to a radio run for a homicide in the 2400 block of Elvans
    Road, S.E.    While responding, Officer Williams and another officer saw a
    Chevrolet Impala collide with a lamp post near the scene of the homicide. After
    Williams and a colleague removed the occupants from the Impala, the officers
    began to secure the perimeter with crime scene tape. While doing so, the officers
    asked a group of bystanders, including Barkley, to leave the area. The group
    responded by shouting obscenities at the officers and advising the officers that they
    had their hands up “like Michael Brown.”6 Eventually the bystanders, except for
    Barkley, moved away from the scene.
    6
    Michael Brown was the young African-American man killed by police in
    Ferguson, Missouri on August 9, 2014.
    7
    Officer Williams continued to order Barkley to move back, but Barkley
    instead placed his cell phone in Officer Williams‟s face. In the words of the report,
    “Officer Williams then tried to physically push Mr. Barkley back.”          Barkley
    responded, the report continued, “by jumping back and trying to strike Officer
    Williams with his fist.” But Officer Williams “delivered a single, straight strike to
    Mr. Barkley‟s face, causing him to fall over backwards and strike his head on the
    ground.” Barkley was then transported to the hospital, discharged with a broken
    jaw, and charged with two counts of assault on a police officer (one for assaulting
    Officer Williams, the other for assaulting another officer at the scene, Michael
    Johnson). Officer Williams‟s excessive force case was then transferred to the
    United States Attorney‟s Office.
    Attached to the IAD report were statements from three police officers, a
    civilian witness, and Barkley.      These statements, in a few respects, were
    inconsistent with each other and with the IAD report itself concerning who had
    initiated physical contact, Barkley or Williams, and, in particular, whether Barkley
    had made threatening gestures to Officer Williams before the officer‟s “straight
    strike.”
    8
    Based on the IAD report, defense counsel moved for “a dismissal — a
    mistrial. . . . [T]his is Brady.”7 Counsel stressed that, had he received timely
    disclosure of the IAD information, his investigation of the case and, perforce, his
    cross-examination of Officer Couch “would have been different.” The trial court
    agreed that the government had withheld evidence favorable to the defense and
    that its disclosure had been untimely under Brady. The court, however, rejected
    dismissal or a mistrial because the defense had received the IAD report, and any
    prejudice from the delayed disclosure would be “mitigated by the fact that [Officer
    Williams] . . . hasn‟t testified, can be crossed, and the defense can make use of this
    [delayed disclosure] during the course of the trial.” Therefore, concluded the
    court, the “failure to disclose” would not be “outcome determinative here” (the
    result required for a Brady violation).8
    The next day, after the court denied a motion the government had filed for
    reconsideration of its Brady ruling, defense co-counsel informed the court that
    overnight the defense had learned from Barkley‟s attorney about a “cell phone
    7
    See Brady, 
    373 U.S. 83
    .
    8
    See (Herbert) Brooks v. United States, 
    396 A.2d 200
    , 204 (D.C. 1978)
    (“[I]nformation is material if it tends to be outcome-determinative of the case”).
    9
    video of the event.”     The defense also had become aware that the Gerstein9
    affidavit that Officer Williams had filed to support Barkley‟s arrest was “not
    completely consistent with the IAD report.” In particular, counsel proffered that
    Barkley‟s attorney had told him, contrary to the officer‟s affidavit, that Barkley
    “was not in a fighting position” toward Williams. And, added counsel, there was
    an issue “about whether or not [Williams] lied in the Gerstein application” and
    about whether other officers “colluded in the lies.”
    The trial court again denied counsel‟s request for Brady sanctions, ruling
    that it would not dismiss, grant a mistrial, or even “continue the case.” The court
    limited cross-examination to (1) the fact that Officer Williams had an investigation
    “pending against him,” including the “underlying facts and circumstances”; (2) the
    “nature of the allegation”; and (3) any potential consequences of the investigation.
    Later, however, having announced that defense counsel could cross-examine about
    the “underlying facts and circumstances” of the Barkley incident, the court
    narrowed that permission by precluding cross-examination about the “underlying
    details” of that incident — the ruling that presents the central issue in this appeal.
    9
    Gerstein v. Pugh, 
    420 U.S. 103
     (1975).
    10
    The jury found Smith guilty of all four charges, and the court sentenced him
    to twenty-four months of incarceration. He subsequently filed a motion for a new
    trial pursuant to Super. Ct. Crim. R. 33, asserting among other things that the trial
    court had erroneously precluded him from cross-examining Officer Williams on a
    “corruption bias” theory (referring to alleged falsities in Officer Williams‟s
    Gerstein affidavit). The trial court denied the motion, noting that it had allowed
    counsel to pursue a “mostly speculative” corruption bias theory and that “there was
    not sufficient evidence to support a claim of corruption bias beyond the
    questioning permitted by the [c]ourt.” Referring to appellant‟s argument that he
    had not been able to “conduct a meaningful impeachment” of Officer Williams
    with respect to inconsistencies between the Gerstein and statements by other
    witnesses to the Barkley incident, the court observed that this was “essentially the
    same argument the defendant made at trial” and that the “[c]ourt does not find, on
    this record, [that] the arguments advanced by defense counsel established a basis
    for cross-examination on the issue of corruption bias.”
    II. Cross-Examination for Corruption Bias
    Smith contends, first, that the trial court violated his Sixth Amendment right
    to cross-examine Officer Williams on a theory of “corruption bias,” discernible
    from the officer‟s false testimony under oath about the Barkley incident. The
    11
    government responds that Smith did not adequately raise at trial, and thus preserve
    for our review, the corruption bias theory he asserts on appeal.
    A. The Right of Confrontation
    The Confrontation Clause of the Sixth Amendment “guarantees a defendant
    in a criminal case the right to confront witnesses „against him.‟” 10 Inherent in this
    right is the opportunity to cross-examine witnesses for bias,11 “a broad term that
    may refer both to a witness‟[s] personal bias for or against a party and to his or her
    motive to lie.”12 Although the trial court has “discretion to control the extent of
    cross-examination[,] . . . [t]hat broad discretion cannot . . . justify a curtailment
    which keeps from the jury relevant and important facts bearing on the
    trustworthiness of crucial testimony.”13           Moreover, “[c]ross-examination
    10
    Longus v. United States, 
    52 A.3d 836
    , 849 (D.C. 2012) (quoting U.S.
    CONST. amend. VI).
    11
    See In re C.B.N., 
    499 A.2d 1215
    , 1218 (D.C. 1985).
    12
    Coles v. United States, 
    36 A.3d 352
    , 358 (D.C. 2012) (quoting McCloud
    v. United States, 
    781 A.2d 744
    , 752 (D.C. 2001)) (citation and internal quotation
    marks omitted).
    13
    In re C.B.N., 
    499 A.2d at 1218
     (citations and internal quotation marks
    omitted).
    12
    concerning bias is particularly important where, as here, the credibility of the key
    government witness is the central factor to be weighed by the trier of fact.”14 Thus,
    “[a] trial court‟s refusal to allow questioning about facts indicative of [a witness‟s]
    bias from which the jury could reasonably draw adverse inferences of reliability is
    an error of constitutional dimension.”15          Furthermore, a defense effort to
    demonstrate bias is not limited to cross-examination.         Because bias is “not a
    collateral issue,” a defendant may “introduce extrinsic evidence,”16 including
    witnesses and documents, to establish it.
    B. Smith’s Allegation of Corruption Bias
    Seeking clarification of the defense effort to cross-examine Officer
    Williams, the trial court first, as background for discussion, expressed at length its
    understanding of our Longus decision17 explaining “corruption bias” — more
    14
    
    Id.
     (citing Davis v. Alaska, 
    415 U.S. 308
    , 317 (1974)).
    15
    Longus, 
    52 A.3d at 852
     (quoting Cunningham v. United States, 
    974 A.2d 240
    , 245 (D.C. 2009)) (internal quotation marks omitted).
    16
    In re C.B.N., 
    499 A.2d at 1218
     (citation and internal quotation marks
    omitted).
    17
    See Longus, 
    52 A.3d 836
    .
    13
    specifically, “a distinct subset of bias evidence”18 demonstrating “a willingness to
    give false testimony.”19 Next, because defense counsel had stressed that he would
    have cross-examined Officer Couch differently if he had first learned about the
    Barkley incident, the court asked how the “pending investigation involving Officer
    Williams” would have affected counsel‟s approach to the Officer‟s colleague,
    Couch. Defense counsel replied that he could have brought out “collusion,” that is,
    “how the officers protect each other” — how they “get together” and “prepare their
    story.” He referenced not only Couch20 but also statements of the other police
    witnesses attached to the IAD report. Counsel added that he was also seeking to
    demonstrate Williams‟s effort to “curry favor” with the prosecution.
    Later that day, however, in a written response to the government‟s motion
    for reconsideration of the court‟s Brady ruling that the Barkley disclosure had been
    untimely, defense counsel clarified that, in alleging collusion, the defense was
    fundamentally asserting corruption: “If Officer Williams lied about the incident,
    and colluded with his fellow officers to support his false version, then he corrupted
    18
    
    Id. at 852
     (citation omitted).
    19
    Vaughn v. United States¸ 
    93 A.3d 1237
    , 1266 n.33 (D.C. 2014).
    20
    Officer Couch was not present at the Barkley incident but was mentioned,
    presumably, as a corrupt colluder at Smith‟s trial.
    14
    the judicial process.”21 More specifically, claimed counsel, witness statements in
    the IAD report and, potentially, Barkley‟s cell phone video of the event possessed
    by Barkley‟s attorney, were “not consistent with the police version.”
    In disputing Smith‟s first contention on appeal — the alleged
    unconstitutional limitation on defense counsel‟s cross-examination of Officer
    Williams for corruption bias — the government maintains that the trial court did
    not err for three reasons: (1) defense counsel never attempted to cross-examine
    Officer Williams “about alleged false statements in the Gerstein affidavit” (which
    the trial court “never precluded”); (2) counsel made mere “passing references” to
    discrepancies in the Gerstein affidavit while arguing, instead, a “collusion bias”
    theory at trial;22 and (3) counsel proffered only “minor inconsistencies” among
    Officer Williams‟s trial testimony, his Gerstein affidavit, and the witness
    statements attached to the IAD report, thus failing to proffer the foundation — at
    21
    The defense response cited one of our “corruption bias” decisions, In re
    C.B.N., 
    499 A.2d at 1219
     (The “essential discrediting element is a willingness to
    obstruct the discovery of the truth by manufacturing or suppressing testimony”)
    (citation omitted).
    22
    According to the government‟s understanding, and ours as well, Smith‟s
    “collusion bias” theory was premised on alleged evidence that police officers, who
    (he says) commonly cover for each other, colluded with Officer Williams in lies —
    “all made up [of] almost exactly the same statement” in the IAD report — about
    how the Barkley incident (and Williams‟s role in it) unfolded.
    15
    least a “well-reasoned suspicion” — required to justify cross-examination for
    corruption bias.23 We consider each in turn.
    1.
    The government‟s first argument is misleading. Defense counsel sought to
    test the accuracy of Officer Williams‟s Gerstein affidavit by reference to allegedly
    contrary testimony by police and other witnesses to the Barkley incident. Thus, he
    established on cross-examination that Williams was under investigation for an
    alleged “serious use of force” in another case, and that Williams had “issued a
    straight strike in defense of myself against [Barkley]” meaning a “jab” that is
    justified when “someone comes to attack you and they raise their hands.”
    Counsel then attempted to ask Officer Williams on cross-examination whether “the
    individual that you hit . . . had his hands up.”         The trial court, however,
    immediately sustained the government‟s objection to the question, reminding
    counsel that he could go into “the nature of the incident” but not “the underlying
    details.”    Counsel protested, in vain, that he had information from Barkley‟s
    attorney that Barkley “had his hands up” in surrender mode; “he was not in a
    fighting position.” Contrary to the government‟s representation, therefore, this left
    23
    Coates v. United States, 
    113 A.3d 564
    , 575 (D.C. 2015).
    16
    little, if any, room for counsel to cross-examine Officer Williams about allegedly
    false statements in the Gerstein affidavit.
    2.
    The government‟s second contention also fails. The government suggests
    (without insisting) that collusion bias and corruption bias — a bias not premised on
    cooperation with others — are distinct forms of bias, and that the corruption theory
    was not raised at trial. The differences between the two, however, are not as
    dissimilar as the government apparently would have it.             “Collusion” bias
    presupposes “[a]n agreement to defraud another or to do or obtain something
    forbidden by law,”24 whereas “corruption” bias can be merely an individual‟s
    “willingness to give false testimony”25 — a “willingness to obstruct the discovery
    of the truth.”26 Both, however, can permeate trial testimony and, by hiding the
    truth, corrupt the judicial process. The fact that more than one actor participates in
    24
    Collusion, BLACK‟S LAW DICTIONARY (10th ed. 2014) (defining
    “collusion”). “The use of dictionary definitions is appropriate in interpreting
    undefined statutory terms.” West End Tenants Ass’n v. George Washington Univ.,
    
    640 A.2d 718
    , 727 (D.C. 1994) (citation omitted).
    25
    Vaughn, 93 A.3d at 1266 n.33.
    26
    Coates, 113 A.3d at 572 (footnote omitted).
    17
    collusion bias cannot negate the corrupt mentality of each participant who, as a
    colluder, seeks to do something “forbidden by law” — in this case obstruct
    discovery of the truth. In the present trial context, therefore, corruption bias can be
    understood as a subset of alleged collusion bias.
    In any event, not only did defense counsel argue at trial that Officer
    Williams had “corrupted the judicial process,”27 but also the trial court itself, in
    denying Smith‟s motion for a new trial, acknowledged that it “did allow counsel to
    pursue a corruption bias theory[,] although the theory was mostly speculative.”
    Accordingly, contrary to the government‟s argument, Smith‟s theory of the case
    presented on appeal had been raised at trial, albeit unsuccessfully.
    3.
    a. The Issue
    We consider, finally, the government‟s only substantive objection to the
    proffered corruption bias: Given only “minor inconsistencies” between Officer
    Williams‟s Gerstein affidavit and the witness statements attached to the IAD
    27
    See supra note 21 and accompanying text.
    18
    report, the defense did not make a “proffer of corruption bias” sufficient to justify a
    ruling that Smith‟s Sixth Amendment confrontation right had been violated.
    Smith sought to demonstrate, through cross-examination, that Officer
    Williams had “lied in his Gerstein affidavit” — evidence that Williams would
    make “false claims under oath in order to justify arrests and criminal charges.”
    Counsel proposed to do so, as we have noted, by showing material inconsistencies
    (including omissions) between the Gerstein affidavit and witness statements in the
    IAD report and, potentially, evidence in Barkley‟s cell phone video possessed by
    his attorney.28
    Before pursuing a particular line of corruption bias questioning, “a defendant
    must lay a foundation sufficient to permit the trial judge to evaluate whether the
    proposed question is probative of bias.”29 To lay that foundation, defense counsel
    must proffer “some facts which support a genuine belief that the witness is biased
    in the manner asserted or, lacking such facts, at least a well-reasoned suspicion [of
    28
    Smith also maintains that the trial court‟s refusal to permit him to
    sufficiently pursue corruption bias was not harmless error under Chapman v.
    California, 
    386 U.S. 18
    , 24 (1967) (“harmless beyond a reasonable doubt”).
    29
    Blades v. United States, 
    25 A.3d 39
    , 42-43 (D.C. 2011) (citations
    omitted).
    19
    bias] rather than an improbable flight of fancy.”30 “At a minimum, this would . . .
    require that the questioner [ ] support any proposal for cross-examination with a
    credible statement describing the suspected cause of bias in the witness, supported
    by plausible factual allegations or itself plausible within the framework of facts
    that neither party has contested.”31 A trial court, however, “does not abuse its
    discretion by precluding cross-examination where the connection between the facts
    cited by defense counsel and the proposed line of questioning is too speculative to
    support the questions.”32
    b. The Defense Proffers
    In this case, after a brief continuance granted to the government to file for
    reconsideration of the trial court‟s Brady ruling, defense counsel sought to show
    30
    Coates, 113 A.3d at 575 (emphasis added) (brackets in original)
    (footnotes and internal quotation marks omitted). See also Clayborne v. United
    States, 
    751 A.2d 956
    , 963 (D.C. 2000) (“The examiner must have a reasonable
    factual foundation, such as the credible report of another witness or one‟s client, or
    at least a „well-reasoned suspicion‟ that the circumstances indicating bias might be
    true.”).
    31
    Melendez v. United States, 
    10 A.3d 147
    , 152 (D.C. 2010) (alteration and
    brackets in original) (citations and internal quotation marks omitted).
    32
    Brown v. United States, 
    683 A.2d 118
    , 125 (D.C. 1996) (brackets,
    citation, and internal quotation marks omitted).
    20
    Smith‟s corruption bias through three proffers, one written, two oral. In his written
    proffer,33 defense counsel stressed that the Gerstein affidavit omitted any reference
    to the fact that Barkley had been “filming . . . the event” on his cell phone; that his
    “video [was] not consistent with the police version that Mr. Barkley dropped the
    phone to assume a fighting pose”; and that although civilian witnesses were
    present “filming the scene,” none had been interviewed and apparently their cell
    phone footage was not available. Later, in his first oral proffer, defense counsel
    pointed out that in Officer Williams‟s Gerstein affidavit, he had laid out facts that
    were contradicted by other witnesses to that incident cited in the IAD report —
    facts that were likely revealed in video footage from Barkley‟s cell phone
    apparently possessed by the U.S. Attorney‟s office. During further proceedings,
    Smith‟s counsel added a second oral proffer by informing the court (as noted
    above) that Barkley‟s attorney had told him that Barkley “was not in a fighting
    position” toward Williams, thereby directly contradicting the Gerstein affidavit.
    Counsel then noted that, in addition to Barkley‟s cell phone video, which he
    “believe[d] the U.S. Attorney‟s office” possessed, there was also “another video
    . . . out there somewhere in the world.”
    33
    This proffer is contained in Smith‟s reply to the government‟s motion to
    reconsider the trial court‟s ruling that the mid-trial Brady disclosure of the pending
    investigation of Officer Williams was untimely.
    21
    Limited by these proffers, we must conclude that the trial court did not err in
    precluding Smith‟s proposed line of corruption bias questioning, for he failed to
    proffer facts sufficient to support the required “well-reasoned suspicion” that
    Officer Williams falsified his Gerstein affidavit, the predicate for Smith‟s
    contention.
    We consider, first, the referenced cell phone videos.        Defense counsel
    initially appears to have understood from Barkley‟s attorney that there was a film
    of virtually the entire Barkley-Williams encounter — a film he continued to
    believe was “somewhere out in the world.” By the time counsel filed Smith‟s
    response to the government‟s motion to reconsider the Brady ruling, however,
    counsel had narrowed his focus to Barkley‟s own cell phone video, apparently
    recognizing and accepting the unavailability of cell phones that other witnesses
    may have been using to film the ruckus. Smith therefore relied exclusively on
    Barkley‟s cell phone (which he believed the U.S. Attorney‟s office possessed) for
    evidence that Barkley had not assumed a fighting stance before Officer Williams
    delivered the strike that felled him.
    In his Gerstein affidavit, Officer Williams averred that Barkley‟s “fist” had
    been “above his chest” in an “aggressive fighting stance” before Officer Williams
    22
    delivered the straight strike. The IAD report is consistent with that statement; it
    concluded that, when Williams ordered Barkley to “back up,” Barkley had
    “plac[ed] his cell phone directly in Officer Williams‟ face,” whereupon Williams
    tried to “push Barkley back,” then Barkley “tried to strike Officer Williams with
    his fist,” at which point the officer struck Barkley. Barkley‟s own statement
    attached to the IAD report adds little; he asserted that he had been “videotaping the
    crash” when the “phone was knocked out of [his] hand.” In this fast-moving
    situation, it is not clear exactly when or how the phone left Barkley‟s hand. But
    even if we assume that Barkley was holding it just before he got hit, there is little
    indication that Barkley could have video-photographed both himself and Officer
    Williams sufficiently to confirm Smith‟s contention that the officer had lied
    because Barkley‟s hands were not up in an “aggressive fighting stance”
    immediately before Williams struck him (as stated in the Gerstein affidavit).
    We turn, next, to Smith‟s contentions comparing the Gerstein affidavit with
    the IAD report. There were, indeed, inconsistencies between the Gerstein affidavit
    and witness accounts of the incident in the IAD report, particularly regarding
    whether Officer Williams initially pushed Barkley and whether Barkley‟s hands
    were up in surrender mode or in a fighting stance at the time Officer Williams
    struck him. But those proffered inconsistencies were not enough to generate a
    23
    “well-reasoned suspicion” that Officer Williams, through his Gerstein affidavit,
    was corrupt — was intentionally “thwart[ing] the ascertainment of truth.”34
    In the Gerstein affidavit, Officer Williams stated under oath (where relevant
    here):
    [1] Officer Williams in a loud clear voice instructed
    Defendant Barkley to move down the sidewalk once
    more but he did not comply. [2] Officer Williams began
    to redirect Defendant Barkley from the crime scene when
    he began shoving Officer Williams. [3] Officer Williams
    issued several loud verbal commands to Defendant
    Barkley to stop and that he was pushing an Officer
    [Johnson]. [4] Defendant Barkley then took an [sic]
    aggressive fighting stance, placing his left foot forward,
    bawled his hands into fists and placed them above his
    chest[;] his elbows were bent at a forty-five degree angle,
    as he began to step toward Officer Williams again. [5]
    Officer Williams, fearing he was about to be struck by
    Defendant Barkley issued a straight [sic] strike to
    Defendant Barkley. [6] Defendant Barkley fell to the
    ground and was placed into handcuffs. [7] Defendant
    Barkley was subsequently placed under arrest for APO
    [assault on a police officer] and transported to Howard
    Hospital by Ambulance . . . .
    The IAD report of the same transaction stated in relevant part:
    34
    See Coates, 113 A.3d at 572 (footnote omitted).
    24
    [1] All the men except Mr. Barkley moved back. Mr.
    Barkley continued to shout . . ., stating that he had his
    hands up and he was not moving. [2] Officer Williams
    continued to order Mr. Barkley to back up, [3] at which
    time, Mr. Barkley responded by placing his cell phone
    directly in Officer Williams‟ face. [4] Officer Williams
    ordered Mr. Barkley to move the phone out of his face,
    but Mr. Barkley did not comply. [5] Officer Williams
    then tried to physically push Mr. Barkley back, [6] who
    responded by jumping back and trying to strike Officer
    Williams with his fist. [7] Officer Williams then
    delivered a single strike to Mr. Barkley‟s face, [8]
    causing him to fall over backwards and strike his head on
    the ground.
    Antwann Barkley added two statements that were attached to the IAD
    report.
    [1] I was trying to film and an officer smacked my phone
    out of my hand. [2] After that an unknown person
    punched me in my face [3] knocking me to the ground[;]
    [4] my hands were up when this happened.
    I were videotaping the crash with my left hand up[;] my
    phone was knocked out of my hand and I were punched
    from the back side . . . . Don‟t remember anymore.
    The IAD report also included statements from four witnesses: three police
    officers and one civilian — statements we shall compare with the Gerstein
    affidavit to discern, if possible, the evidence of corruption bias that Smith alleges.
    Like the government, we perceive only minor inconsistencies, not larger
    differences, among the Gerstein affidavit, the IAD report, and the eyewitness
    25
    statements. The comparisons do not manifest discernible lies, let alone corruption
    bias, attributable to Officer Williams.
    First, the Gerstein affidavit said that Officer Williams “instructed” Barkley
    to leave the scene.      Similarly, the IAD report and all three officers said,
    respectively, that Williams “tried to guide,” “directed,” and “order[ed]” Barkley to
    leave — no obviously rough treatment at the outset of the confrontation. The
    civilian witness made no comparable assessment.
    Second, as to what followed next, in the Gerstein affidavit Officer Williams
    averred that Barkley “began shoving” him. Similarly, one officer stated that,
    initially, Barkley tried to “push hard” on Williams. To the contrary, the IAD report
    said that, after Barkley failed to comply with Officer Williams‟s order to remove
    the phone from his face, Williams was the first to “physically push” Barkley.
    Moreover, another officer also said that initially Williams “began to push”
    Barkley. The third officer and the civilian witness did not comment about the first
    “shove” or “push.”
    26
    Third, the Gerstein affidavit averred that when Barkley “began shoving”
    Williams, the officer “began to redirect” (meaning push)35 Barkley from the crime
    scene and commanded Barkley to stop pushing a colleague (Officer Johnson).
    Barkley then assumed an “aggressive fighting stance” toward Williams (described
    in detail), whereupon Williams, in fear, “issued a straight strike” that knocked
    Barkley to the ground. The IAD report — stating that Williams, not Barkley,
    initiated physical contact — added that when Williams tried to “physically push”
    Barkley, Barkley tried to “strike Officer Williams with his fist,” whereupon
    Williams “delivered a single strike” to Barkley‟s face, causing Barkley to fall to
    the ground. In addition, a civilian witness, as well as two of the three officers, all
    stated that Barkley acted from a “fighting stance,” “an aggressive stance,” “balled
    . . . fists.” The third officer referred only to Barkley‟s “movement.” The IAD
    report did not say that Barkley had assumed an “aggressive” or “fighting” stance,
    but it did conclude that Barkley was “jumping back,” meaning “back” at Williams,
    before “trying to strike” the officer (who thereafter felled Barkley).
    35
    Ostensibly, “redirect” seems rather benign. However, we learned from
    the transcript of Officer Williams‟s testimony at Barkley‟s later (2015) trial for
    assaulting Officers Williams and Johnson that in police-speak “redirect” means
    “push.” Appellant Smith filed an unopposed motion to supplement the record on
    appeal with the Gerstein affidavit and the Barkley trial transcript.
    27
    c. The Law
    Although the “well-reasoned suspicion” standard does not require defense
    counsel to prove that the factual allegations proffered are true,36 counsel must
    proffer more than minor sequential inconsistencies stated by different individuals
    whose varied perceptions of a single frenzied event may well differ.37         Such
    differing accounts do not necessarily indicate that someone is lying or, without
    more, show corruption, the bias that Smith asserts. This conclusion is particularly
    justified when evaluated with reference to our corruption bias case law explaining
    when a proffer has been deemed sufficient.
    36
    Brown, 
    683 A.2d at 125
     (“[A] proffer is nothing more than an offer to
    prove factual allegations, and does not consist of their proof itself.”).
    37
    It is interesting to note that eleven months later, when Barkley was
    acquitted at his trial for assaulting two police officers (Williams and Johnson), the
    trial judge called the scene “very chaotic. . . . There were many people. There
    were a number of officers.” In particular, “Officer Williams was really focused on
    what he thought was [a] potential homicide investigation, that maybe people
    involved in this crash were witnesses, or involved in a homicide, and that was his
    focus. He had gotten these people out of the car. He had handcuffed them. He
    was trying to secure them, and so, his focus was, although he may have been
    concerned about the other officers in cordoning off the scene, his focus really was
    to maintain the status quo until the homicide detectives arrive[d].”
    28
    For example, in Longus,38 a murder case, we discerned reversible Sixth
    Amendment error in the trial court‟s refusal to allow cross-examination and
    “extrinsic evidence” tending to prove the corruption bias of a police witness who,
    according to a newspaper account proffered by counsel — which the government
    had conceded was “not inaccurate” — had allegedly coached witnesses to change
    their stories in another homicide case and was under suspension and investigation
    for “witness coaching.”39 In Coates,40 we reversed a murder conviction because of
    a trial court ruling that denied the defense an opportunity to present “[e]xtrinsic
    evidence” that an “informant had corruptly fabricated a murder confession by an
    innocent man in another case in order to curry favor with the government.”41 And
    in In re C.B.N.,42 we reversed an adjudication of armed robbery after the trial court
    had refused a defense proffer of “extrinsic evidence” tending to prove that the
    government‟s only identification witness had blackmailed other boys at the scene
    38
    Longus, 
    52 A.3d 836
    .
    39
    
    Id. at 852-53
    .
    40
    Coates, 
    113 A.3d 564
    .
    41
    
    Id. at 566-67
    .
    42
    In re C.B.N., 
    499 A.2d 1215
    .
    29
    of the robbery by saying that “he would give testimony that would get them all in
    trouble” unless they gave him money.43
    These decisions addressing alleged bias appropriately considered defense-
    proffered reliance on extrinsic evidence indicating corruption — a “propensity or
    willingness” to lie.44 That is to say, they presuppose extrinsic evidence “probative
    not merely of [the witness‟s] lack of veracity, but of his corruption — his
    willingness to obstruct the discovery of the truth by manufacturing or suppressing
    testimony or otherwise to thwart the ascertainment of truth in a judicial
    proceeding.”45
    The defense proffers in the present case do not reach this “propensity or
    willingness” threshold, a hurdle that can only be surmounted by a proffer of
    evidence, extrinsic to the case, tending to demonstrate that the witness is likely a
    43
    
    Id. at 1217
    .
    44
    Longus, 
    52 A.3d at 852
     (quoting Bennett v. United States, 
    763 A.2d 1117
    ,
    1123 (D.C. 2000)). See Vaughn v. United States, 
    93 A.3d 1237
    , 1266 n.33 (D.C.
    2014) (“willingness to give false testimony”); In re C.B.N., 
    499 A.2d at 1219
    (“willingness to lie upon the stand”).
    45
    Coates, 113 A.3d at 572 (footnote and internal quotation marks omitted).
    30
    prevaricator.46 The alleged evidence of corruption here, based almost exclusively
    on the Gerstein affidavit and the IAD report with related police and civilian
    witness statements, is too fuzzy to suggest more than confusion.            Officer
    Williams‟s Gerstein affidavit and the IAD materials have only three noteworthy
    differences: (1) The Gerstein indicates that Barkley “shov[ed]” Williams first,
    whereas the IAD report concludes that Williams “physically push[ed]” Barkley
    first. (2) The Gerstein is silent about Barkley‟s cell phone, whereas the IAD report
    states that Barkley placed his cell phone in Williams‟s face, whereupon the officer
    tried to push Barkley back when Barkley would not remove the phone. (3) The
    Gerstein did not mention whether Barkley‟s hands were up in surrender mode,
    whereas the IAD stated that Barkley shouted that “he had his hands up” and “was
    not moving.”
    Neither the first distinction (while a sharp one) nor the second one is,
    without more, a manifest indication of bias.       However, the third distinction,
    46
    In using the words “extrinsic evidence,” we are not suggesting that the
    evidence must always be admissible at trial in order for the court to find it
    sufficient to justify the required well-reasoned suspicion; rather, we use those
    words to represent facts proffered about the witness from information outside the
    purview of the trial. This means facts that would satisfy the court that a suspicion
    of corruption bias was well reasoned and thus warranted cross-examination to that
    end, leaving it to the court to decide in what manner that information would be
    conveyed at trial.
    31
    focused on the acceleration of events, reflects a more serious issue of intent and
    possible prevarication. But even if we assume that Barkley‟s hands were “up” in
    surrender mode initially, the two police officers and the civilian witness who gave
    statements about the “strike” by Williams, all supported the IAD conclusion that
    Barkley had tried “to strike Officer Williams with his fist” before Williams
    “delivered [his] single strike” to Barkley‟s jaw. Moreover, in support of that
    conclusion, the civilian witness, as well as two of the three police officers (the
    other did not comment), signed statements that, before Williams delivered his
    strike, Barkley was in an “aggressive” or “fighting” stance.47
    The differences between the testimony of Officer Williams and the IAD
    report and witnesses may reflect a dent in the officer‟s veracity — his credibility
    — but they do not, without more, give rise to a “well-reasoned suspicion” of a
    corruption bias against Barkley. Moreover, our conclusion is reinforced by the
    very absence of the collusion bias that Smith alleges as bedrock evidence of the
    47
    In addition to Smith‟s proffer concerning Barkley‟s cell phone video
    discussed above, Smith‟s proffered information from Barkley‟s attorney — that
    Barkley “was not in a fighting position” toward Officer Williams — was
    inadmissible hearsay and in any event belied by both civilian and police IAD
    witnesses. Finally, Smith‟s generalized proffer that other civilian witnesses were
    present merely reflected IAD evidence, without specifics as to what the witnesses
    would say in addition to statements attached to the IAD report.
    32
    alleged corruption.48 Given several dissimilar memories among the police officers
    in their IAD statements, as well as the similar memories of police officers and the
    civilian witness attesting to Barkley‟s aggressive stance toward Williams before
    the officer leveled his single strike, the trial court could reasonably conclude that
    there was no nefarious collusion here. In sum, absent a sharp and meaningful
    distinction between Officer Williams‟s Gerstein affidavit and the reported
    statements of the IAD witnesses about this fast-moving situation, we do not have
    extrinsic evidence of an established level of prevarication sufficient to support a
    “well-reasoned suspicion” that Officer Williams had acted corruptly in signing his
    Gerstein affidavit and testifying as he did at trial.
    III. Impeachment of Allegedly False Testimony
    Smith contends, next, that the trial court erred in precluding impeachment of
    Officer Williams after he “falsely and repeatedly” testified that he had been
    “attacked and acted in self-defense” when striking Barkley.
    48
    See supra part II.B.
    33
    In addition to attempting to cross-examine Officer Williams for alleged bias,
    the defense sought to challenge his veracity. As we have observed earlier,49 when
    asked about breaking Barkley‟s jaw, the officer acknowledged that he had “issued
    a straight strike in defense of myself against [Barkley]” that caused him to fall to
    the ground. But, he added, “whether or not the straight strike broke his jaw or the
    ground did, I don‟t know.” Referring to Barkley, defense counsel then asked
    Williams: “[T]he individual that you hit, he had his hands up, correct?” The
    government objected. Counsel replied that Williams had “opened the door” to
    cross-examination about information, received from Barkley‟s attorney, “that the
    guy had his hands up and he was not in a fighting position.” Defense counsel, in
    other words, was attempting to show that the officer was lying — that he had not
    struck in self-defense.     The trial court, however, sustained the government‟s
    objection, reminding counsel that he could ask “about the nature of the incident”
    but not about “the underlying details.”       The court later signaled, in denying
    appellant‟s new-trial motion, that it would not permit a “trial-within-a-trial” of the
    Barkley incident — a diversion that would likely confuse the jury.50 Thus, the
    49
    See supra part II.B.1.
    50
    See Hager v. United States, 
    791 A.2d 911
    , 914 (D.C. 2002) (“The trial
    judge must balance the probative value of the evidence against the risk of
    prejudicial impact, including the risk of jury confusion from a trial-within-a-trial,
    (continued . . .)
    34
    court chose to halt an inquiry that seemed headed in that direction. The court
    advised that counsel could ask Williams about whether he thought the investigation
    pending against him was “a big deal,” and “whether he is [being] investigated for
    breaking somebody‟s jaw,” but he could not go “into more detail about the events.”
    On appeal, Smith cites “a rule of evidential parity: once [a party] opens the
    door to a specific issue, the [opponent] has the right to respond with contrary
    evidence on the same issue.”51          Thus, says Smith, because Officer Williams
    attempted to justify his “straight strike” against Barkley as self-defense, Smith‟s
    counsel had the right to challenge that testimony through cross-examination.
    Ordinarily, Smith‟s point would be well-taken.        Moreover, we are not
    convinced that the trial court would necessarily have launched a distracting mini-
    trial by permitting cross-examination on a question about Williams‟s self-defense
    claim.        In light of that reasonable concern, however, the court might have
    approached counsel‟s effort more creatively by permitting a voir dire on the issue,
    ________________
    (. . . continued)
    and may exclude marginally relevant evidence if it will distract the jury from the
    issue in this case.”) (internal citations and quotation marks omitted).
    51
    Johns v. United States, 
    434 A.2d 463
    , 469 (D.C. 1981).
    35
    outside the presence of the jury, to explore appropriate guidelines for how far the
    questioning might go without generating jury confusion.52
    On the other hand, even if the court had permitted defense counsel to ask
    whether Barkley‟s hands were “up,” and Williams answered “yes,” he presumably
    would have explained that “up” meant (in the words of the Gerstein affidavit) “an
    aggressive fighting stance” causing him fear followed by the “straight strike.”53 A
    contrary answer — that Barkley‟s hands were up in surrender mode — would have
    been at odds with the scenario in Williams‟s Gerstein affidavit and thus unlikely.
    On the other hand, if, in answering the “hands up” question, Officer Williams were
    to have acknowledged that, early on, Barkley‟s hands were up in a benign stance,
    he presumably would have added a qualifier: that by the time of the “straight
    strike,” Barkley was standing in attack mode, as several IAD witnesses, police and
    52
    See Shorter v. United States, 
    792 A.2d 228
    , 235 (D.C. 2001) (“[T]he trial
    court‟s concern about a mini-trial and jury confusion could have been alleviated
    through a limited voir dire examination outside the presence of the jury, and
    depending upon the results of the voir dire, limited cross-examination of [the
    complainant] about the . . . alleged incident and her recantation.”).
    53
    See supra part II.B.3.
    36
    civilian, confirmed.54 In sum, Smith‟s argument that the “hands up” question was
    likely to help the defense amounts to speculation.
    Furthermore, the government, in closing argument to the jury, confirmed
    that, as to his pending investigation, Officer Williams was a resistant witness, and
    that defense counsel had effectively exposed the officer‟s equivocal, defensive
    responses. Said the prosecutor:
    At first, Mr. Williams — Off. Williams wasn‟t so sure
    about what — exactly what the consequences [of his
    pending investigation] are, and that‟s pretty surprising,
    that he may not grasp some of the severity of what‟s
    going on. But when asked on cross-examination about
    the consequences, he recognized that he could lose his
    job as an officer of the Metropolitan Police Department;
    he could face criminal charges for felony assault; and he
    also could face civil litigation based on the events that
    occurred in the early morning hours. Now, the reason
    that this is all important is because the stakes of that
    investigation leave you to wonder, is there a reason this
    officer has to change his testimony here, to testify
    favorably for the government in this case? And that‟s
    something that you guys are charged with considering
    when you go back to that jury room.
    54
    Perhaps Smith could have argued that, because he was challenging
    Williams for bias as well as veracity, he could have introduced extrinsic evidence,
    such as a Barkley witness, in aid of impeachment. But that would have launched
    the mini-trial that the trial court was determined, with sound reason, to avoid.
    37
    From the government‟s viewpoint, therefore, defense counsel gave the jury good
    reason to question Officer Williams‟s credibility, without regard to whether
    Barkley‟s hands may have been “up” in surrender — not in attack mode — when
    Williams struck him.
    Finally, from defense counsel‟s colloquy with the trial court, it is clear that
    counsel was pushing for a mini-trial of the Barkley incident, not merely for an
    answer to the “hands up” question. Adding this dynamic into the mix, we cannot
    gainsay the trial court‟s discretionary judgment that setting a Barkley inquiry in
    motion would likely overwhelm the proceeding with a mini-trial.55 But even if the
    trial court should at least have deferred that concern by trying to find a way to test
    the “hands up” question through a reasonably limited voir dire (not heard by the
    jury), we cannot say, on this record, that there was an abuse of discretion — a
    discretionary error of a “magnitude to require reversal”56 — when the court
    sustained the government‟s objection to that question. The situation was too fluid,
    and Barkley‟s “fighting stance” before the Williams “strike” was too well
    documented, for us to grant heft to Smith‟s argument here.
    55
    See (Markus) Johnson v. United States, 
    960 A.2d 281
    , 294 (D.C. 2008)
    (“The judge must retain full authority to prevent this sort of trial-within-a-trial.”)
    (citation omitted).
    38
    IV. The Brady Claim
    Relying on Brady v. Maryland,57 Smith maintains that the delayed disclosure
    of the Barkley incident violated his right to constitutional due process, warranting
    reversal.58 The government and the trial court agreed with Smith that the incident,
    as reported by the IAD, was “bias information.” Moreover, the court, quoting
    Vaughn v. United States, agreed that the information was “potentially useful to the
    defense”59 and, in derogation of Brady, had not been “timely provided.”60 The
    court concluded, however, that the delayed disclosure was not “material” under
    ________________
    (. . . continued)
    56
    (James) Johnson v. United States, 
    398 A.2d 354
    , 366 (D.C. 1979).
    57
    
    373 U.S. 83
     (1963).
    58
    See Giglio v. United States, 
    405 U.S. 150
    , 154 (1972) (nondisclosure of
    impeachment information falls within Brady protection).
    59
    See Vaughn, 93 A.3d at 1254.
    60
    See id. We have said that, “[t]o determine on appeal whether the
    government, through its representatives in the trial court, has violated its
    obligations under Brady, we consider: (1) whether the information in question is
    „favorable to the accused‟; (2) whether this information was possessed and
    suppressed by the government, „either willfully or inadvertently‟; and (3) whether
    that information was material, i.e., whether there is „a reasonable probability that,
    had the evidence been disclosed, the result of the proceeding would have been
    different.‟” Id. (quoting Miller v. United States, 
    14 A.3d 1094
    , 1109 (D.C. 2011)).
    39
    Brady61 — that is, the delay would not be “outcome-determinative.”62 Thus, the
    court twice denied counsel‟s requests for dismissal or a mistrial.        The court
    reasoned, as noted earlier, that any prejudice to the defense would be “mitigated”
    through cross-examination of Officer Williams at trial. That ruling, however,
    came too quickly.
    Although cross-examination of Officer Williams might have mitigated
    prejudice from late disclosure of the Barkley incident, the defense argument at trial
    — not sufficiently acknowledged by the court — was that cross-examination for
    corruption bias would be prejudiced without further investigation of the officer‟s
    interactions with Barkley.      Thus, the “critical inquiry” here is “whether the
    tardiness” in disclosing the Barkley incident mid-trial — without opportunity for
    further investigation — “prevented defense counsel from employing the [Brady]
    material to good effect.”63 Indeed, “[t]he ability to mount an effective cross-
    examination often is of great significance in delayed disclosure cases involving
    61
    See supra note 60.
    62
    (Herbert) Brooks, 
    396 A.2d at 204
     (“[I]nformation is material if it tends
    to be outcome-determinative of the case”).
    63
    United States v. Perez-Ruiz, 
    353 F.3d 1
    , 8 (1st Cir. 2003) (quoting United
    States v. Devin, 
    918 F.2d 280
    , 290 (1st Cir. 1990)).
    40
    impeachment evidence.”64      Understandably, therefore, after denial of defense
    counsel‟s first request for a mistrial but before Officer Williams was to testify,
    counsel asked for “a day” to “digest” the IAD report, a request the court denied on
    the assumption that counsel would “have some additional time” when trial
    presumably would be delayed to arrange counsel for Officer Williams.65
    Rather than pursue a lawyer for Williams, however, the government asked
    for, and received, a brief continuance, beginning shortly after 2:00 p.m., to prepare
    a motion for reconsideration of the court‟s Brady ruling, due at 7:00 that evening,
    before the second day of trial. Defense counsel was ordered to file a response by
    12:00 noon the following day, thereby compressing his time to prepare for cross-
    examination of Officer Williams and delivery of closing argument.             Smith
    contends on appeal that if he had received adequate time to investigate the Barkley
    incident with the benefit of the IAD report — more than the overnight time he had
    — his “cross-examination of Officer Williams would have been more effective,”
    and he “would have been able to expose Officer Williams‟ corruption bias.”
    64
    Id. at 9.
    65
    Defense counsel made his request for a continuance, on the first day of
    trial, before his discovery that evening that Barkley‟s attorney had a cell phone
    video of the Barkley incident as well as other information indicating the need for
    further, substantial investigation.
    41
    To be sure, from the moment of the Brady disclosure after opening
    statements to the jury, defense counsel persistently sought time to investigate,
    process, and use the information contained in the IAD report. Although counsel
    made only the one explicit request for a “continuance,”66 he cannot be faulted for
    not asking for another.67 There can be no doubt that the court was aware of
    Smith‟s desire (after denial of his requested dismissal or a mistrial) to have
    additional time, both when defense counsel received the IAD report and again after
    the conversation counsel had with Barkley‟s attorney, when counsel learned that
    there were “witnesses in a cell phone video of the event.” Counsel also had
    located Officer Williams‟s Gerstein affidavit, which, he told the court, “was not
    completely consistent with the IAD report.”        Based on this new information,
    counsel again stressed to the court that “Mr. Smith has been denied the right to
    investigate[,] to figure out how to integrate that [evidence] into his defense.”
    66
    See supra note 65 and accompanying text.
    67
    Cf. Miller, 
    14 A.3d at 1115
     (“[G]iven the judge‟s view of the case and his
    comparatively tolerant attitude towards belated disclosures, a motion for a mistrial
    would surely have been futile, and the law generally does not require the doing of a
    futile act”) (citing In re Melton, 
    597 A.2d 892
    , 907 (D.C. 1991) (en banc)).
    42
    On the second day of trial, in Smith‟s reply to the government‟s motion for
    reconsideration, counsel outlined the investigation he would have conducted had
    he been provided the information of Officer Williams‟s pending investigation “in a
    timely manner.” He said that he would have “interviewed the three lay witnesses”
    identified by Barkley‟s attorney, viewed the cell phone video “that directly
    contradicts Officer Williams‟ account,” attempted to locate “any other cell phone
    video,” and “sought copies of the relevant police reports.” Moreover, defense
    counsel represented that the three witnesses whom Barkley‟s attorney had
    identified “dispute[d] Officer Williams‟ and his fellow officers‟ account[s]” in the
    Gerstein affidavit and the IAD report. Based on defense counsel‟s submissions,
    therefore, the trial court was undoubtedly aware that he was pleading for further
    time to conduct his investigation, but the court ruled sua sponte that it would “not
    continue the case.”
    All things considered, we must conclude that Smith has preserved, and
    effectively asserted, a claim that the trial court erred in denying a reasonable mid-
    trial continuance to explore the potential for relevant evidence of corruption
    beyond that proffered through the Gerstein affidavit and the IAD report. Indeed,
    43
    courts regularly favor a mid-trial continuance over a dismissal or mistrial when an
    untimely Brady disclosure can reasonably be remedied in that way.68
    “We review [a trial court‟s] decision to deny a continuance for abuse of
    discretion,”69 an analysis, first, of alleged error and, if error is found, of alleged
    prejudice “of a magnitude to require reversal.”70 “A party seeking a continuance
    must make a showing that it is reasonably necessary for a just determination of the
    cause.”71 More specifically, “in the delayed disclosure context,” there must be, in
    68
    See, e.g., United States v. Mota, 
    685 F.3d 644
    , 649 (7th Cir. 2012)
    (“[W]hen a defendant realizes that exculpatory evidence has been withheld, the
    appropriate course is to seek a continuance if more time to investigate the
    exculpatory potential of the evidence is needed”) (citations and internal quotation
    marks omitted); United States v. Williams, 
    95 F.3d 723
    , 730 (8th Cir. 1996)
    (finding the district court acted within its discretion in granting defendant a two-
    week continuance after a Brady violation, rather than dismissing the case).
    69
    Perez-Ruiz, 
    353 F.3d at 8
     (applying abuse of discretion standard to denial
    of a continuance after delayed disclosure of Brady/Giglio material). See generally
    Moctar v. United States, 
    718 A.2d 1063
    , 1065 (D.C. 1998) (“As we have
    repeatedly held, the grant or denial of a continuance rests within the sound
    discretion of the trial judge, to whom we accord wide latitude.”).
    70
    (James) Johnson, 
    398 A.2d at 366
    . Accord Dorsey v. United States, 
    154 A.3d 106
    , 120 (D.C. 2017) (citing Jones v. United States, 
    127 A.3d 1173
    , 1189
    (D.C. 2015)).
    71
    Kyle v. United States, 
    759 A.2d 192
    , 196 n.2 (D.C. 2000) (citations and
    internal quotation marks omitted).
    44
    addition to showing error, “some showing of prejudice beyond mere assertion.”72
    Factors relevant to this two-fold showing include “the reasons for the request for a
    continuance, the prejudice resulting from its denial, the party‟s diligence in seeking
    relief, any lack of good faith, and prejudice to the opposing party.” 73 “The trial
    court also may properly consider the public‟s interest in the prompt, effective, and
    efficient administration of justice.”74   Furthermore, because constitutional due
    process is at issue here, the importance of that right is still another, indeed
    significant, factor to be considered.
    Smith stresses in his brief that if the government had timely disclosed the
    Barkley incident (as it could have) well before trial,75 defense counsel could have
    72
    Perez-Ruiz, 
    353 F.3d at 8
    . See Mackabee v. United States, 
    29 A.3d 952
    ,
    963-64 (D.C. 2011) (“[I]t is not enough for appellant to describe a mere possibility
    that [the] undisclosed information might have helped the defense, or might have
    affected the outcome of the trial”) (footnote and internal quotation marks omitted).
    73
    (DeAndre) Brooks v. United States, 
    130 A.3d 952
    , 960 (D.C. 2016)
    (quoting Daley v. United States, 
    739 A.2d 814
    , 817 (D.C. 1999)).
    74
    
    Id.
     (quoting Leak v. United States, 
    757 A.2d 739
    , 744 (D.C. 2000))
    (internal quotation marks omitted).
    75
    The Barkley incident was referred to the United States Attorney‟s Office
    on the day it happened, December 1, 2014; the IAD report was dated December 9,
    2014, and the incident was disclosed to Smith‟s counsel, along with the report,
    after opening statements and testimony by the government‟s first witness on
    December 17, 2014. Officer Williams testified that he became aware of the
    (continued . . .)
    45
    “ask[ed] for a continuance” prior to swearing of the jury, “to investigate further
    and modify the defense theory, opening statement, cross-examination of Officer
    Williams[,] and closing argument.”76        The prejudice from the government‟s
    delayed disclosure, he asserts, was even greater because Officer Williams was the
    main prosecution witness.
    For reasons we shall explain forthwith, we shall assume, hypothetically, a
    successful compromise with the trial court that would have allowed Smith, during
    a mid-trial continuance, a measure of access to Barkley witnesses theretofore
    barred by the court‟s protective order.        And, relatedly, we shall assume a
    satisfactory solution to the court‟s concern that the proceeding not drift too far into
    a mini-trial of the Barkley incident. Even in light of these assumptions, however,
    as we shall elaborate, Smith‟s claims of trial court error and prejudice, taken
    together, ultimately fail to satisfy Brady‟s materiality requirement. That is to say,
    by resolving these issues through assumptions in Smith‟s favor, and merging those
    ________________
    (. . . continued)
    investigation well in advance of trial, believing that he had received notification
    “three days after it happened.”
    76
    Perez v. United States, 
    968 A.2d 39
    , 66 (D.C. 2009) (This disclosure
    must be made at such a time as to “allow[] defense counsel an opportunity to
    investigate the facts of the case and, with the help of the defendant, craft an
    appropriate defense”).
    46
    assumptions into the question whether the court‟s denial of a reasonable
    continuance would have created a “material” deprivation under Brady, we must
    answer “no.”     There was no “reasonable probability” that “the result of the
    proceeding would have been different”77 if the continuance had been granted and
    Smith had pursued the midtrial investigation he proffered.
    An enhanced pretrial or midtrial investigation building on the Gerstein
    affidavit and the IAD report, when coupled with resourceful cross-examination of
    Officer Williams, would not have “undermine[d] [our] confidence in the
    outcome,”78 for ultimately nothing leads to a conclusion that Smith did not receive
    a “fair trial.”79 As noted earlier,80 Smith filed an unopposed motion to supplement
    the record on appeal with the Gerstein affidavit and the two-day transcript from
    77
    Vaughn, 93 A.3d at 1254 (citation omitted). “A „reasonable probability‟
    is a probability sufficient to undermine confidence in the outcome.” United States
    v. Bagley, 
    473 U.S. 667
    , 682 (1985). Under this standard, a “showing that it is
    more likely than not the defendant would have been acquitted” is not required.
    Vaughn, 93 A.3d at 1262. Rather, “the materiality threshold is met if, in the
    absence of proper disclosure, we question whether the defendant received a fair
    trial and our „confidence‟ in the outcome of the trial is thereby „undermine[d].‟”
    Id. (footnote and citation omitted).
    78
    Bagley, 
    473 U.S. at 682
    ; Vaughn, 93 A.3d at 1263.
    79
    See Bagley, 
    473 U.S. at 682
    ; Vaughn, 93 A.3d at 1263.
    80
    See supra note 35 and accompanying text.
    47
    Barkley‟s bench trial. Thereafter, the government sought to remove any reference
    in its filings that opposed consideration of the Barkley trial. Both parties therefore
    concur in our reliance on that record for purposes of assessing materiality under
    Brady. To us it is clear that even if, during Smith‟s trial, his counsel had access to
    all the testimonial and other evidence admitted during Barkley‟s trial, we must
    conclude that Smith‟s argument for corruption bias by Officer Williams would
    have failed.
    We have already observed that the discrepancies between the Gerstein
    affidavit of Officer Williams and the IAD report (and attendant statements) were
    insufficient, without more, to generate a “well-reasoned suspicion” that Williams
    harbored a corruption bias.     When we add to those documents the evidence
    presented in the Barkley proceeding, the totality of the evidence reinforces that
    conclusion.
    In the first place, contrary to defense counsel‟s surmise, Smith was not
    prejudiced by counsel‟s inability to track down Barkley‟s cell phone video and
    other video footage for use at trial. According to the judge in the Barkley trial, the
    “surveillance video from, I assume . . . a pharmacy . . . doesn‟t really show very
    48
    much.”81 Furthermore, “[w]ith regard to the cell phone video that was recovered
    from Mr. Barkley, . . . I really don‟t think it really helps very much in resolving the
    important issues in this case.”      Counsel for Smith does not question those
    observations.82
    As to the testimony concerning Barkley‟s alleged assaults against Officers
    Williams and Johnson, the judge appeared to credit testimony that Barkley (in the
    judge‟s words) told his friends to “keep your hands up so you‟re not perceived to
    be a threat to these officers.” Thereafter, according to Officer Williams, he “began
    to redirect [Barkley],” i.e., “push him back towards the crime scene tape,”
    acknowledging (contrary to his Gerstein affidavit) that he pushed Barkley first.
    The judge then found that, in response to that push, Barkley pushed back.
    Barkley‟s response was “not . . . unreasonable,” added the judge, because Barkley
    had “not really [been] doing anything but mouthing off,” and Officer Williams
    “had no right to put his hands on Mr. Barkley or [ ] push him.” Instead, said the
    judge, the officer should have arrested Barkley “for failure to obey a lawful
    81
    As indicated earlier, Smith‟s counsel had believed that a video of the
    Barkley encounter in addition to the one in Barkley‟s cell phone was “out there in
    the world,” but he did not argue that the U.S. Attorney‟s office had it or assert the
    importance of finding it for purposes of Smith‟s trial.
    82
    Neither party provided video footage for the record on appeal.
    49
    command.” Therefore, concluded the judge, “because the officer . . . was the
    initial aggressor,” and Barkley‟s response was “reasonable,” the judge found
    Barkley not guilty of APO.       The acquittal, therefore, turned on the officer‟s
    unreasonably “putting his hands on Mr. Barkley” in the first place, not on an
    inappropriate direct strike in response to Barkley‟s “aggressive stance” once the
    situation had escalated in this “very chaotic scene.”83
    It is important to emphasize that, by the time of Officer Williams‟s
    testimony at Barkley‟s trial, approximately nine months after the present
    proceeding, he had abandoned his Gerstein statement and accepted the finding of
    the IAD report that he had pushed Barkley before Barkley shoved him. And in
    further testimony, Williams confirmed that Barkley‟s followers had “had their
    hands up, saying Michael Brown, Michael Brown,” and that Barkley kept “telling
    them to keep their hands up” in passive reaction to the police.84
    83
    The trial judge observed that, once Barkley “got into” a “fighting stance,”
    the judge had “no doubt that maybe Officer Williams thought [Barkley] was about
    to punch him, and maybe [Williams] was completely okay with, you know, giving
    the straight-line punch.”
    84
    It is interesting to note that the Barkley trial judge added: “I can say one
    thing about Officer Williams, he was amazingly honest and, and credible. I found
    . . . Officer Williams very, very credible in many ways. . . . Sometimes I think the
    honesty of, and I appreciated it, of Officer Williams may actually have helped the
    defense case.”
    50
    Based on the evidence at Barkley‟s trial, we are convinced that if Smith had
    been given a reasonable mid-trial continuance to investigate that incident further
    — including reasonable access to the cell phone and other video evidence in the
    government‟s possession, plus reasonable access to cooperative eyewitnesses —
    there is reason to believe that Smith would have (1) learned that the video material
    was not likely to help the defense; (2) discovered the essential validity of the IAD
    report, including evidence that Barkley had faced Officer Williams initially with
    his hands up; (3) learned that contrary to his Gerstein affidavit, Williams
    acknowledged he had pushed Barkley before Barkley shoved him; and (4)
    uncovered that — as corroborated by two officer witnesses and a civilian witness
    — Barkley had “got into a fighting stance” before the officer jabbed him with the
    “straight strike.”
    The question whether denial of a continuance here was “material” under
    Brady — creating a “reasonable probability” that further investigation would have
    led to a different result — is an objective inquiry, not merely a question answerable
    by reference to how a particular trial judge subjectively would have viewed the
    matter.85 Thus, in making that objective analysis, we do not rely on the Barkley
    85
    See Bagley v. Lumpkin, 
    798 F.2d 1297
    , 1301 (9th Cir. 1986) (“The proper
    inquiry is an objective one: whether the Government‟s failure to . . . disclos[e]
    (continued . . .)
    51
    judge‟s credibility findings,86 which we have included only to provide a complete
    story of that trial as context for Officer Williams‟s testimony. Rather, for Brady
    purposes, we rely solely on the officer‟s responses during that trial to indicate what
    Smith‟s counsel presumably would have learned from cross-examination of Officer
    Williams in this case, if the trial court had permitted it. We are confident that
    when Officer Williams‟s Barkley testimony is added to the IAD report and
    attendant statements, no reasonable factfinder would have found that his testimony
    in this case reflected corruption bias — a propensity or willingness to lie — that
    would have led to a different result here. In sum, the trial court did not abuse its
    discretion in denying a continuance that would have allowed Smith‟s counsel to
    investigate further the actions of Officer Williams in the Barkley incident.
    ________________
    (. . . continued)
    information that might have been helpful in conducting cross-examination
    undermines confidence in the outcome of the trial. Therefore, the district judge
    erred when . . . he stated that the [undisclosed information] would not have
    affected his decision. The inquiry is not how this or any other judge, as the trier of
    fact, would subjectively evaluate the evidence. It is, rather, how the absence of the
    evidence objectively might have affected the outcome of the trial.”) (internal
    citation and quotation marks omitted).
    86
    This court has accepted trial court credibility findings during a Brady
    analysis when essential to assessing relevance of facts germane to materiality. See,
    e.g., Perez, 
    968 A.2d at 72
     (in assessing materiality of government‟s failure to
    disclose alleged false statements and immigration status of a witness, “[w]e
    defer[red] to the trial court‟s credibility determination” that the witness “did not
    fabricate her trial testimony . . . to curry favor with the government in order to
    obtain help with her immigration status”).
    52
    Although, as noted earlier, the court erred in failing to grant a continuance, that
    error did not result in an “abuse” — an error “of a magnitude to require reversal.”87
    *****
    For the reasons spelled out above, the judgment of the trial court is
    Affirmed.
    87
    (James) Johnson, 
    398 A.2d at 366
    .
    53
    THOMPSON, Associate Judge, concurring: I concur in the judgment and also
    fully concur with Judge Ferren‟s opinion, except with respect to his conclusion that
    appellant‟s “theory of the case presented on appeal [was] raised at trial.” Ante at
    17. My review of the record persuades me that the trial court was not adequately
    apprised that defense counsel was pursuing not just a collusion-bias theory but also
    a corruption-bias theory as to Officer Williams. That is another reason why, in my
    view, the trial court did not err in precluding appellant‟s proposed line of
    questioning.
    Defense counsel made multiple statements to the court that indicated that
    counsel wanted to pursue a collusion-bias theory. For example, on December 18,
    2014, when the trial court asked counsel to explain “why a pending investigation
    involving Off. Williams . . . is related . . . to your ability . . . to raise [a] bias
    issue,” defense counsel said, “First, I think there‟s an issue of collusion[.]”
    Counsel further explained that “the issue is how the officers protect each other”
    since “they all make similar statements as to what happened, going as far as
    characterizing [William‟s punch to Barkley] as a straight punch.” Counsel said
    that his “overall theme” was that “officers — when you know your [fellow] officer
    is in trouble and he‟s under an investigation, these officers get together in collusion
    and they prepare their story.” Counsel added that “it‟s about establishing that this
    54
    unit, this is what they do when they are faced up against allegations of excessive
    force,” i.e., “in that incident where [an arrestee] was hurt, they all ma[k]e up
    almost the exact same statement.”1 Counsel told the court that the “other issue”
    was that Officer Couch had the same motive to curry favor with the U.S.
    Attorney‟s Office as Officer Williams had, “because that‟s his partner.” Counsel
    also said that investigating complaining witness Barkley, the witnesses in the
    Barkley case, obtaining the video footage, and exploring contradictions with
    Williams‟s Gerstein “[a]ll . . . would have [gone] to [that] theory.”2
    1
    On December 17, too, counsel had asserted to the court that Officer Couch
    may have “kn[o]w[n] about Off. Williams‟s investigation and may have been
    trying to cover for him.” He told the court that he contemplated a “simple bias
    cross” focused on Couch‟s possibly “currying favor” on behalf of Williams.
    Counsel said that with earlier disclosure about the investigation pending against
    Officer Williams, he might also have “gone down the road that Mr. Williams is
    actually the person that assaulted Mr. Smith.”
    2
    Counsel explained that there was “a sworn affidavit that Damien Williams
    swore to in terms of the Gerstein that he made basically laying out the facts of that
    underlying case, and . . . there are things that contradict that.” Shortly thereafter
    co-counsel interjected that the issue was “also about whether or not [Williams] lied
    in the Gerstein application, whether or not the officers that were part of that event
    on December 1st colluded in the lies.” These, co-counsel said, were “core issues
    of credibility.” Co-counsel did not mention corruption bias. The trial court said
    that it would permit counsel “to set up this theory that . . . Off. Couch cover[ed]
    up[] because he‟s partners with . . . Off. Williams[.]” On December 19, appearing
    to follow up on co-counsel‟s comments, counsel told the court that he wanted to
    cross-examine Williams not just as to bias (presumably, collusion bias) but also as
    to “his veracity as he started to speak about the underlying incident regarding self-
    (continued . . .)
    55
    During the further proceedings on December 18, 2014, counsel also told the
    court that Barkley‟s attorney had told him that Barkley was not in a fighting
    position. But counsel then went on to argue that the purpose of the questions he
    wanted to ask Williams about the incident was to establish “the nature of the
    injuries” Barkley suffered and to show that this was “not just a run-of-the-mill
    investigation” and not a “big deal.” Again, counsel did not say that the purpose
    was to show that Williams was a corrupt officer.
    In appellant‟s “Reply to Government‟s Motion to Reconsider” its Brady
    ruling, defense counsel perhaps came close to urging the theory he advances on
    appeal, but even there the theory was tied to a collusion theory. That pleading
    asserted, “there is evidence of collusion here. If Officer Williams lied about the
    incident, and colluded with his fellow officers to support his false version, then he
    has corrupted the judicial process.”       In the same vein, counsel‟s pleading
    emphasized that Williams might be facing charges of aggravated assault or assault
    with significant bodily injury and stated that Williams‟s “conduct, and that of his
    ________________
    (. . . continued)
    defense.” The court responded that there was “sufficient information in the record
    from which the jury can judge the credibility of this officer.”
    56
    partner, [was] critical to the defense theory.” Defense counsel‟s presentations
    never advanced the argument that counsel wanted to cross-examine to establish
    that Williams gave a false account of what happened during the Barkley incident
    and, on that basis alone, was shown to be a corrupt cop who was not credible
    regarding his claim that Smith threw a gun into a yard while being chased by
    police.
    The various statement‟s by appellant‟s trial counsel were a far cry from
    appellant‟s argument now that “[t]rial counsel proposed to demonstrate corruption
    bias by eliciting that Officer Williams lied in his Gerstein affidavit, thus acting to
    obstruct the discovery of truth by manufacturing or suppressing his own
    testimony.”3 Given the various statements by counsel, I believe the trial court
    cannot be faulted for limiting counsel‟s questioning in the way the court did with
    respect to what the court fairly regarded as a “speculative” theory.4 Further, for the
    3
    As Judge Ferren‟s opinion acknowledges, defense counsel may argue that
    there is “a dent in [a witness‟s] veracity — his credibility,” ante at 31, and that
    there are inconsistencies between a witness‟s account of a “frenzied event” and the
    account given by other individuals, ante at 27, without thereby necessarily arguing
    that the witness has the propensity to lie that inheres in a claim of corruption bias.
    4
    I read the court‟s statements in its ruling denying appellant‟s motion for a
    new trial as confirmation that counsel‟s argument led the court to understand that
    (continued . . .)
    57
    reasons Judge Ferren‟s opinion explains, the IAD report, which the court reviewed,
    did not suggest a basis for the theory of corruption bias that appellant now
    advances.
    MCLEESE, Associate Judge, dissenting: The opinion for the court holds that
    the trial court permissibly precluded cross-examination of Officer Damien
    Williams about whether Officer Williams made false statements in a sworn
    affidavit in connection with an unrelated matter. I respectfully dissent.
    I.
    The opinion for the court lays out the evidence at trial and the procedural
    context of the ruling at issue. Ante at 3-10. I agree that Mr. Smith adequately
    ________________
    (. . . continued)
    counsel was pursuing a theory of collusion bias. The court stated at page 14 of its
    order that it “did allow counsel to pursue a corruption bias theory although the
    theory was mostly speculative.” “Speculative” was the word the court had used
    during the proceedings on December 18 in response to defense counsel‟s collusion
    theory. The court explained that there was not “support in the record for allowing
    [counsel] to use the claim of how all the officers in the two separate cases that are
    not related are backing each other up,” but, nevertheless, noted that counsel had
    made his point in cross-examining Officer Couch and also said that it would permit
    the defense to examine Officer Couch again.
    58
    preserved a challenge to that ruling. Ante at 16-17. I do not agree, however, with
    the court‟s holding that the ruling was permissible. Ante at 17-37.
    The Confrontation Clause of the Sixth Amendment “guarantees a defendant
    in a criminal case the right to confront witnesses against him.” Longus v. United
    States, 
    52 A.3d 836
    , 849 (D.C. 2012) (internal quotation marks omitted). That
    right is violated if the trial court “precludes the defense from pursuing a line of
    examination that is necessary to enable the jury to fully evaluate the witness‟s
    credibility.” 
    Id. at 850-51
    .
    Mr. Smith sought to cross-examine Officer Williams about an unrelated
    incident in which Officer Williams arrested a man named Antwann Barkley. Mr.
    Smith contended that Officer Williams‟s sworn statements about the incident
    demonstrated Officer Williams‟s corruption bias, i.e., that Officer Williams had
    shown a “willingness to obstruct the discovery of the truth by manufacturing or
    suppressing testimony or otherwise to thwart the ascertainment of truth in a
    judicial proceeding.” Coates v. United States, 
    113 A.3d 564
    , 572 (D.C. 2015)
    (internal quotation marks omitted). Such conduct “bears directly on the veracity of
    the wrongdoer in testifying at a trial.” Longus, 
    52 A.3d at 852
     (internal quotation
    59
    marks omitted); cf. In re C.B.N., 
    499 A.2d 1215
    , 1219 (D.C. 1985) (“The
    willingness to testify falsely goes to the core of the witness‟[s] credibility . . . .”).
    We have held that an attorney seeking to cross-examine a witness about
    corruption bias “need only proffer some facts which support a genuine belief that
    the witness is biased in the manner asserted or, lacking such facts, at least a well-
    reasoned suspicion of bias rather than an improbable flight of fancy.” Coates, 113
    A.3d at 575 (internal quotation marks, brackets, and footnote omitted); cf. Moore v.
    United States, 
    114 A.3d 646
    , 655 (D.C. 2015) (“[T]he requirement of a reasonable
    factual foundation is a fairly lenient one. It simply calls for a credible good faith
    proffer of facts supporting a genuine belief or well-reasoned suspicion[,] . . .
    [which] may be based on plausible factual allegations . . . .”) (internal quotation
    marks and footnote omitted).
    The trial court has discretion to impose reasonable limits on cross-
    examination. See, e.g., Brown v. United States, 
    683 A.2d 118
    , 124 (D.C. 1996)
    (cross-examination may be restricted “within reasonable limits to avoid such
    problems as harassment, prejudice, confusion of the issues, the witness‟[s] safety,
    or interrogation that is repetitive or only marginally relevant”) (internal quotation
    marks omitted). Nevertheless, the Confrontation Clause precludes limits on cross-
    60
    examination that “keep[] from the jury relevant and important facts bearing on the
    trustworthiness of crucial testimony.” Coates, 113 A.3d at 573 (internal quotation
    marks omitted); see also Hagans v. United States, 
    96 A.3d 1
    , 31 (D.C. 2014) (trial
    court may not “preclude a meaningful degree of cross-examination that allows the
    defense to pursue the proposed line of cross-examination in sufficient depth to
    elicit the nature and extent of the witness‟s bias”) (internal quotation marks
    omitted).
    Under this framework, I conclude that the trial court erred in precluding
    cross-examination of Officer Williams on the theory that Officer Williams
    intentionally made false statements in a sworn affidavit about Mr. Barkley‟s arrest.
    The United States has not disputed that submitting an intentionally false affidavit
    would demonstrate corruption bias. Nor has the United States adequately disputed
    that Mr. Smith was required to demonstrate only a “well-reasoned suspicion” in
    order to have a sufficient factual basis to cross-examine Officer Williams about
    corruption bias. It was not until oral argument that the United States advanced the
    argument that there is “tension” between the “well-reasoned suspicion” standard
    this court applied in cases such as Coates and the approach taken in cases such as
    Sherer v. United States, 
    470 A.2d 732
    , 738-39 (D.C. 1983) (upholding trial court‟s
    preclusion of cross-examination of witness about witness‟s alleged perjury in
    61
    unrelated trial, because defense counsel‟s proffer of proof of prior perjury was
    conclusory and contested by United States); see also Roundtree v. United States,
    
    581 A.2d 315
    , 321 (D.C. 1990) (“Where an accused seeks to impeach the
    credibility of a witness by offering evidence that the witness has made a false
    claim under similar circumstances, the confrontation clause mandates that the trial
    court give defendant leave to cross-examine about the prior claim only where it is
    „shown convincingly‟ that the prior claim is false.”) (citing Sherer). This court
    generally will not consider arguments made for the first time at oral argument, see,
    e.g., Scott v. Burgin, 
    97 A.3d 564
    , 565 n.2 (D.C. 2014), and I therefore would
    decide this case under the “well-reasoned suspicion” standard.
    In my view, the information proffered by defense counsel at trial sufficed to
    permit defense counsel to plausibly argue that Officer Williams‟s sworn affidavit
    about Mr. Barkley‟s arrest was knowingly false.        According to the affidavit,
    Officer Williams “began to redirect” Mr. Barkley “when [Mr. Barkley] began
    shoving Officer Williams,” at which point Mr. Barkley adopted a fighting stance
    and approached Officer Williams. Also according to the affidavit, it was at that
    point that Officer Williams struck Mr. Barkley.       In contrast, defense counsel
    proffered information indicating that Mr. Barkley had not taken any threatening
    actions at the time that Officer Williams struck Mr. Barkley. Specifically, defense
    62
    counsel pointed to: (1) Mr. Barkley‟s account of the incident as reflected in the
    IAD Report, which states that Mr. Barkley had been trying to photograph the
    incident when an officer knocked his cell phone out of his hand and someone
    punched him in the face from behind; and (2) statements by Mr. Barkley‟s attorney
    that three witnesses disputed Officer Williams‟s account and that video footage
    from Mr. Barkley‟s cell phone was inconsistent with the police version that Mr.
    Barkley dropped his cell phone and assumed a fighting stance.
    The information proffered by defense counsel did not definitively establish
    that Officer Williams intentionally submitted a false affidavit, nor did it necessarily
    demonstrate that Officer Williams probably did so. But the proffered information
    did reasonably support the line of cross-examination that defense counsel sought to
    undertake. Cf., e.g., Longus, 
    52 A.3d at 853
     (defense counsel provided adequate
    basis to support cross-examination of witness on corruption bias, where proffer
    “did not manufacture allegations of bias out of thin air,” but instead relied on
    newspaper account and fact of “government‟s suspension and investigation” of
    witness) (internal quotation marks omitted).
    The United States argues, however, that this court‟s cases have required the
    trial court to permit cross-examination as to a witness‟s alleged corruption bias
    63
    only where the government had concluded that the witness had in fact acted
    corruptly. That proposed limitation is not consistent with either our articulation or
    our application of the “well-reasoned suspicion” test. See, e.g., Longus, 
    52 A.3d at 852-54
     (finding that trial court erred in precluding questioning of detective on
    corruption bias, where detective was subject of pending investigation for allegedly
    coaching witnesses in another case but there was no indication that government
    had concluded that detective in fact had improperly coached witnesses).
    In denying Mr. Smith‟s new-trial motion, the trial court expressed concern
    that permitting cross-examination about Mr. Barkley‟s arrest would have led to a
    “trial-within-a-trial” about that incident.      Although that is a legitimate
    consideration, we have held that such considerations “cannot justify a curtailment
    [of bias cross-examination] which keeps from the jury relevant and important facts
    bearing on the trustworthiness of crucial testimony.” Coates, 113 A.3d at 573
    (internal quotation marks omitted).
    For these reasons, I would hold that the trial court erred by precluding cross-
    examination of Officer Williams as to whether the sworn affidavit concerning Mr.
    Barkley‟s arrest was intentionally false.     I am not persuaded by the contrary
    conclusion of the opinion for the court. First, the opinion for the court states that
    64
    the differences among the various accounts of Mr. Barkley‟s arrest are “minor” and
    therefore “do not necessarily indicate that someone is lying.” Ante at 24, 27. I do
    not view the differences between Officer Williams‟s account and the defense
    proffer as minor. On Officer Williams‟s account, Mr. Barkley apparently made
    first physical contact, Mr. Barkley shoved Officer Williams, and Mr. Barkley took
    an aggressive fighting stance before Officer Williams struck Mr. Barkley. On the
    account proffered by the defense, Mr. Barkley apparently did not initiate physical
    contact and had taken no threatening actions before he was struck. The differences
    between those accounts are both stark and of critical significance. On Officer
    Williams‟s account, Mr. Barkley was guilty of assault on a police officer, but on
    the defense‟s account, Mr. Barkley was the victim of an unjustified use of force. It
    is true, as the opinion for the court notes, that the differences between the two
    accounts “do not necessarily indicate that someone is lying.” Ante at 27 (emphasis
    added). But that is not the applicable standard, and the differences between the
    two accounts in my view provided an ample basis for defense counsel to cross-
    examine Officer Williams about whether Officer Williams was lying in the
    affidavit.
    Second, the opinion for the court seems to weigh all of the information
    before the trial court, to determine how strongly that information considered as a
    65
    whole supported a conclusion that Officer Williams had intentionally made false
    statements in the affidavit. Ante at 29-32. That is not our function, nor was it the
    function of the trial court. Rather, the proposed cross-examination should have
    been permitted as long as defense counsel proffered “some facts” supporting a
    “genuine belief” or “well-reasoned suspicion.” Coates, 113 A.3d at 575 (internal
    quotation marks omitted). As we have explained, that “standard is a fairly lenient
    one. Because of the central role that bias cross-examination plays in a criminal
    trial, the court must accord such cross-examination wide latitude and must not
    unduly restrict it.    ...    [C]onsistent with the exploratory nature of cross-
    examination and the leniency of the foundation requirement, the proffer need not
    be particularly compelling.” Blades v. United States, 
    25 A.3d 39
    , 43 (D.C. 2011)
    (brackets, ellipses, citation, and internal quotation marks omitted); cf., e.g., Scull v.
    United States, 
    564 A.2d 1161
    , 1164 (D.C. 1989) (“[W]here counsel has
    information from her own client, which she does not know to be false and which is
    not inherently incredible, she has a sufficient good-faith basis for the proposed
    cross-examination.”) (internal quotation marks omitted).
    66
    II.
    Mr. Smith argues that the preclusion of corruption-bias cross-examination in
    this case requires reversal under the constitutional harmless-error standard of
    Chapman v. California, 
    386 U.S. 18
    , 24 (1967) (to demonstrate harmlessness of
    constitutional error, government must “prove beyond a reasonable doubt that the
    error complained of did not contribute to the verdict obtained”). The United States
    did not dispute in its responsive brief that the Chapman standard applies.
    Although the United States did contend at oral argument that this court should
    instead apply the harmless-error standard applicable to non-constitutional errors,
    that argument came too late. Scott, 97 A.3d at 565 n.2. I therefore would apply
    the Chapman standard. See, e.g., Longus, 
    52 A.3d at 854
     (applying Chapman
    standard where trial court erroneously precluded defense from cross-examining
    witness about corruption bias).
    I cannot say that the preclusion of corruption-bias cross-examination in this
    case was harmless beyond a reasonable doubt. “[C]ross-examination seeking to
    ferret out bias takes on enhanced significance where the credibility of the key
    government witness is in issue.” Cunningham v. United States, 
    974 A.2d 240
    , 245
    67
    (D.C. 2009) (internal quotation marks omitted).      The government‟s evidence
    connecting Mr. Smith to the handgun consisted almost exclusively of the testimony
    of two officers. Officer Williams was a key government witness, because only he
    testified about the retrieval of the handgun. The government emphasized Officer
    Williams in its opening statement and closing argument. Cf. Porter v. United
    States, 
    37 A.3d 251
    , 261 (D.C. 2012) (“As we have frequently observed, a
    prosecutor‟s emphasis on certain evidence is at least a highly relevant measure of
    the prejudicial impact of that evidence.”) (internal quotation marks omitted). On
    cross-examination, Officer Williams gave seemingly evasive responses to defense
    counsel‟s questioning about whether the punch that broke Mr. Barkley‟s jaw was
    an approved defensive maneuver, whether the pending investigation involved
    alleged excessive force, whether Officer Williams was removed from his usual
    duties, and whether he was aware of the severity of the potential consequences of
    the investigation.
    The remaining evidence against Mr. Smith was not overwhelming. The on-
    site photographs of the handgun were taken by Officer Williams on his cell phone,
    rather than by crime-scene personnel. Officer Williams and Officer Couch both
    testified to seeing Mr. Smith throw the handgun over the fence with his left hand,
    but the parties stipulated to evidence suggesting that Mr. Smith was in fact right-
    68
    handed.      No corroborative physical evidence, such as fingerprints or DNA,
    identified Mr. Smith as possessing the handgun. Moreover, defense counsel also
    attempted to impeach Officer Couch‟s testimony, by suggesting that Officer Couch
    had unjustifiably injured Mr. Smith in the course of effectuating the arrest in this
    case.
    Because the trial court precluded the cross-examination at issue, we cannot
    be sure what would have happened at trial if the cross-examination had been
    permitted.     Nevertheless, the United States bears the “heavy burden” of
    demonstrating beyond a reasonable doubt that the precluded cross-examination
    would not have affected the verdict in this case. Coleman v. United States, 
    948 A.2d 534
    , 553 (D.C. 2008). I conclude that the United States has not carried that
    burden. Cf., e.g., Longus, 
    52 A.3d at 841-42, 853-54
     (error in limiting cross-
    examination of detective about allegations that detective had improperly coached
    witnesses was not harmless under Chapman standard; cross-examination could
    have aided defense efforts to impeach government‟s principal witness at trial);
    Coles v. United States, 
    36 A.3d 352
    , 359-60 (D.C. 2012) (error in curtailing cross-
    examination of key government witness at trial about alleged collusion reflecting
    corruption not harmless beyond reasonable doubt; court could not say “that the
    defendant would have been convicted without the witness‟[s] testimony, or . . . that
    69
    the restricted line of inquiry would not have weakened the impact of the
    witness‟[s] testimony”) (internal quotation marks omitted).   I therefore would
    vacate the judgment and remand for further proceedings.