United States v. Yu , 411 F. App'x 559 ( 2010 )


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  •                              UNPUBLISHED
    UNITED STATES COURT OF APPEALS
    FOR THE FOURTH CIRCUIT
    No. 09-4520
    UNITED STATES OF AMERICA,
    Plaintiff – Appellee,
    v.
    THOMAS YU,
    Defendant – Appellant.
    Appeal from the United States District Court for the Eastern
    District of Virginia, at Alexandria. Gerald Bruce Lee, District
    Judge. (1:08-cr-00196-GBL-1)
    Argued:   October 29, 2010               Decided:   December 30, 2010
    Before TRAXLER,   Chief   Judge,   and   DUNCAN   and   KEENAN,   Circuit
    Judges.
    Affirmed by unpublished opinion.        Judge Duncan wrote the
    opinion, in which Chief Judge Traxler and Judge Keenan joined.
    ARGUED: Lisa Hertzer Schertler, SCHERTLER & ONORATO, LLP,
    Washington, D.C., for Appellant.    Jay V. Prabhu, OFFICE OF THE
    UNITED STATES ATTORNEY, Alexandria, Virginia, for Appellee. ON
    BRIEF: Neil H. MacBride, United States Attorney, Andrew
    McCormack, Special Assistant United States Attorney, OFFICE OF
    THE UNITED STATES ATTORNEY, Alexandria, Virginia, for Appellee.
    Unpublished opinions are not binding precedent in this circuit.
    DUNCAN, Circuit Judge:
    This appeal arises from a jury’s conviction of Thomas Yu on
    three counts--alleging possession, receipt, and distribution of
    child pornography--in violation of 18 U.S.C. §§ 2252A(a)(5)(B)
    and    2252A(a)(2).            Yu   claims     the    district     court         abused     its
    discretion         by   limiting     his   cross-examination           of    a   government
    witness and by excluding a defense witness.                           He further argues
    that       the     district     court      erred     with    respect        to     its    jury
    instructions and violated Federal Rule of Criminal Procedure 43
    by delivering an amended version of those instructions to the
    jury in writing, despite his request that it be given in open
    court.       For the reasons that follow, we affirm.
    I.
    A.
    In     August        2006,   federal     authorities       executed         a     search
    warrant       at    the     Illinois    home    of    a    man   named      James      Faulds.
    Investigators learned that Faulds had been operating a computer
    file       server    that     allowed   individuals         to   upload      and       download
    images       of     child    pornography.           They    further    learned          that   a
    computer with an internet protocol address 1 registered to Yu’s
    1
    “Each computer connected to the Internet is assigned a
    unique numerical address, otherwise known as an Internet
    protocol or IP address, to identify itself and facilitate the
    (Continued)
    2
    Virginia home had, on July 20, 2006, uploaded forty-four files
    containing images of child pornography to Faulds’s computer and
    downloaded more than one hundred such files from it.
    Acting    on      this   information,     federal     and     state   law
    enforcement officers executed a search warrant at Yu’s residence
    in February 2007.        Agents seized a variety of items from his
    home, including three desktop computers, two laptop computers,
    and more than one hundred computer disks.            Forensic review of
    these materials revealed, inter alia, more than 9,000 images of
    child pornography and records of Internet searches for terms
    related   to   child    pornography.       Investigators    also    uncovered
    evidence that files containing images of child pornography had
    been created in a folder associated with a peer-to-peer file
    sharing program 2 on multiple occasions.         On October 15, 2008, a
    grand jury indicted Yu on three counts of possessing, receiving,
    and distributing child pornography.
    orderly flow of electronic traffic.”         Peterson v. Nat’l
    Telecomm. & Info. Admin., 
    478 F.3d 626
    , 628 (4th Cir. 2007).
    2
    “[P]eer-to-peer networks permit the users’ computers to
    communicate directly with each other.” United States v. Morace,
    
    594 F.3d 340
    , 343 (4th Cir. 2010) (quoting Metro-Goldwyn-Mayer
    Studios Inc. v. Grokster, Ltd., 
    545 U.S. 913
    , 919-20 (2005))
    (internal quotation marks omitted).
    3
    B.
    We briefly review the proceedings in the district court,
    with particular attention to the disputes that gave rise to Yu’s
    present    claims.      Shortly   after    his     indictment,   Yu   moved    for
    disclosure    of     materials    related    to     the   case   against      him,
    including    any     expert    testimony     the    government    intended      to
    introduce at trial.           In response to Yu’s motion and with the
    government’s agreement, the district court entered a discovery
    order on October 23, 2008.            The order mandated a variety of
    disclosures, including that both parties provide notice of any
    anticipated expert testimony.
    On January 16, 2009, pursuant to the discovery order and
    Federal Rule of Criminal Procedure 16(a)(1)(G), 3 the government
    filed summaries of the testimony to be offered by its two expert
    witnesses.        The government had earlier provided Yu with access
    to   the    raw    computer    data   that    its     forensic    experts      had
    evaluated.        Yu employed his own computer forensic examiner, a
    woman named Tami Loehrs, to review this data.                However, Yu did
    3
    Rule 16(a)(1)(G) provides, in pertinent part, that “[a]t
    the defendant’s request, the government must give to the
    defendant a written summary of any testimony that the government
    intends to use under Rules 702, 703, or 705 of the Federal Rules
    of Evidence during its case-in-chief at trial.”           Expert
    testimony is governed by Federal Rule of Evidence 702.
    4
    not   disclose     any    prospective         expert    testimony--by            Loehrs    or
    anyone else--prior to trial.
    Yu’s jury trial began on February 2, 2009.                        Consistent with
    its   pre-trial    disclosures,          the      government      relied        heavily   on
    expert   testimony       to   link    Yu     to   images    of    child        pornography.
    Immigration      and     Customs      Enforcement       Agent         Joseph    Mizell,    a
    forensic    computer      expert,       testified      about      a    variety     of    data
    extracted from the computers seized from Yu’s home.
    For instance, after reviewing images of child pornography
    found on one of those computers, Mizell noted that the same hard
    drive contained documents that had “the name Thomas Christopher
    Yu written on the bottom of them.”                  J.A. 253.          He observed that
    some of these documents had apparently been accessed on the same
    date as images of child pornography.                   Agent Mizell confirmed the
    presence of similar documents containing Yu’s name on another
    computer on which child pornography had been found.                             He further
    testified that he had not found evidence that anyone else had
    controlled that machine.
    Agent   Mizell      also     testified       about    the       seized     computers’
    Internet browsing histories.               Agent Mizell explained that he had
    extracted material related to child pornography from a larger
    file containing a record of all websites visited on a particular
    computer.     He       referred    to    a   government         exhibit    that     he    had
    prepared    containing        those     portions       of   a    computer’s       browsing
    5
    history related to child pornography.                 The government opted not
    to   introduce    the    computer’s       complete    browsing      histories     into
    evidence.
    Defense    counsel     cross-examined         Agent    Mizell      at   length,
    eliciting a variety of concessions.                 Agent Mizell admitted that
    he had not searched to see if digital records reflected that
    friends of Yu, who might have had access to his computers, had
    used the machines to download the illegal files.                       Agent Mizell
    further conceded that he had focused his analysis on material
    useful to the prosecution and had “omit[ted] certain images”
    that were irrelevant to the search warrant.                  J.A. 311.
    Defense counsel also asked a series of questions about the
    criteria Agent Mizell had followed when excerpting information
    from    the      computers’     browsing        histories.           Agent      Mizell
    acknowledged      that   he   had    “arbitrarily       picked      out    what   [he]
    thought was relevant.”         J.A. 300.         He also stated, as he had on
    direct examination, that the material presented to the jury did
    not reflect the entirety of the computers’ browsing history.                          In
    response to repeated queries by defense counsel, Agent Mizell
    explicitly    acknowledged      on    at    least    seven    occasions        that    he
    could   not   verify     whether     Yu    in   particular    had    conducted        the
    searches reflected in the computers’ browsing histories or had
    actually viewed any of the illegal images.                    See, e.g., J.A. at
    297 (“As you sit here today, you can’t say that Mr. Yu ever
    6
    viewed a single pornographic image; is that right?” “Correct.”);
    id. at 317 (“I take it that you weren’t present and have no
    personal knowledge as to who was using the computer [at] those
    particular times; is that right?” “That’s right.”); id. at 326
    (“[Y]ou can’t say anyone, Mr. Yu or [his friend] or anyone in
    the     world    actually      viewed      that        particular       image       on    that
    particular day?” “No.”).
    During     his    cross-examination             of     Agent    Mizell,        defense
    counsel attempted to introduce three unauthenticated documents,
    which were purportedly prepared by Yu’s forensic examiner, Tami
    Loehrs.        Defense counsel asserted that the first such document
    contained       some    of   the     raw   data        from    which    Agent        Mizell’s
    browsing-history         excerpts     were       drawn.       Over     the    government’s
    objection, the court gave defense counsel the opportunity to lay
    foundation for the document.               Defense counsel asked Agent Mizell
    a     series    of     questions     about       the    material.            Agent       Mizell
    confirmed that Loehrs had accessed the data at issue, but he did
    not know if that information was reflected in the document.                                The
    document was not admitted into evidence.
    Shortly       after   the   first     document         was     rejected,      defense
    counsel asked the court if he could pursue a line of questioning
    designed “to show [Agent Mizell] that there is actually evidence
    on the computer that . . . he chose to ignore that would really
    show    that”    someone     other    than       Yu    had    downloaded      the     illegal
    7
    images.      J.A. 316.        After hearing from both sides, the district
    court     sustained     the    government’s        objection            to   that   line   of
    questioning.
    Defense       counsel    later    referenced       a    second         document   that
    allegedly      contained       part    of   the    seized         computer’s        Internet
    browsing history from a particular date.                           When the government
    objected, defense counsel was given another opportunity to lay
    foundation.         Once again, Agent Mizell was able to confirm that
    defense expert Loehrs had accessed the raw data, but he was
    unable to speak to how she had prepared the document at issue.
    The   government      renewed    its    objection        to       the    use   of   material
    “which was not created by [Agent Mizell]” on cross-examination.
    J.A. 323.      The district court sustained the objection, rejecting
    in the process defense counsel’s argument that the material was
    intended only to refresh Agent Mizell’s recollection.
    Part     way   through     defense        counsel’s         cross-examination        of
    Agent Mizell, court adjourned for the day.                              That evening, Yu
    filed notice, for the first time, of his intent to call Tami
    Loehrs    as   an    expert    witness.         Styled       as    a    Rule   16(a)(1)(G)
    notice, 4 Yu’s motion described Loehrs’s extensive background as a
    4
    Yu’s characterization of his motion notwithstanding,
    defendants’ obligation to disclose information about expert
    witnesses under certain circumstances arises under Federal Rule
    of Criminal Procedure 16(b)(1)(C).   Here, the district court’s
    discovery order created an independent obligation to divulge any
    (Continued)
    8
    computer         forensic     examiner.        It    explained      that    Loehrs    would
    testify about images and other digital material recovered from
    Yu’s       computers        and    describe    evidence      she    found   that     showed
    additional users had access to those machines.                        The motion cited
    Loehrs’s         “experience        and   training    in     the    field   of    computer
    forensic analysis” as the basis for her testimony.                               J.A. 25C.
    It included a twenty-page attachment, consisting of Loehrs’s CV
    and a list of the more than one hundred cases in which she had
    served as an expert witness.
    The next day, the district court ruled that Loehrs could
    not testify as an expert witness.                     The court explained that Yu
    had had months since the entry of the discovery order “to engage
    an expert . . . and disclose any expert opinions” but had failed
    to   do     so    in    a    timely    manner.       J.A.    328.      Defense     counsel
    promptly responded that the expert notice had been filed purely
    as a “prophylactic measure,” as Loehrs was in fact slated to
    testify as a lay witness.                     J.A. 329.       He argued that Loehrs
    would speak only to the “chain of custody” of the data that she
    gathered         from   the       computers 5 and    would    “not    . .    .   offer an
    planned expert testimony.     Yu does not dispute that he                               was
    required to disclose expert testimony in advance of trial.
    5
    The data at issue included the two excerpts from
    computers’ Internet browsing histories noted above, as well as a
    (Continued)
    9
    opinion . . . as to what happened and what didn’t happen.”                          J.A.
    332.     He explained that, to the extent expert testimony was
    necessary,      Yu    intended     to   rely    exclusively       on    the   testimony
    provided by Agent Mizell.
    The   district      court    rejected       Yu’s    recharacterization        of
    Loehrs’s testimony.            The court noted that Yu had engaged Loehrs
    to review forensic data from the seized computers, that she had
    done so, and that she had subsequently prepared charts for use
    by the defense during trial.               The court expressed incredulity at
    defense counsel’s claim that he intended “to prove that [Yu] was
    not    guilty     .   .   .,     relying    sole[ly]      upon    the    government[]
    witness’s       testimony.”        J.A.     331.        Citing    Yu’s    failure    to
    disclose Loehrs’s existence until after the trial had started,
    the    district       court    dismissed       Yu’s     efforts    to    reframe    the
    substance of her testimony as “sandbagging” and precluded her
    from testifying at trial.           J.A. 329.
    The defense ultimately called two lay witnesses to testify
    on    Yu’s   behalf:      Yu’s    sister    and    Yu   himself.         Yu’s   defense
    centered on his argument that a friend of his was responsible
    for downloading the files recovered from the computers and that
    he had been unaware of the files’ presence.                   When pressed by the
    third document that purportedly showed                    when    certain       computer
    files had been most recently accessed.
    10
    government          on    cross-examination,      Yu    conceded    that,    on     his
    theory, his friend had managed to secretly download many of the
    illegal images over a period of years, from a computer located
    in Yu’s bedroom, just “ten to twelve” feet from his bed.                          J.A.
    482-83.        At        the   conclusion   of   Yu’s    testimony,   the    defense
    rested.
    On February 4, 2009, the district court charged the jury in
    open       court.        Its   jury   instructions      included,   inter   alia,    a
    thorough      description        of   the   government’s     burden   of    proof   on
    Count II, receipt of child pornography, § 2252A(a)(2). 6                      Before
    6
    The district court’s oral instruction on Count II was as
    follows:
    Section 2252(a) Subsection(a)(2) of Title 18 of
    the United States Code provides in part that “it is a
    crime for any person who knowingly receives or
    distributes any child pornography that has been mailed
    or shipped or transported in interstate or foreign
    commerce by any means including by computer or any
    material that contains child pornography that has been
    mailed or shipped or transported in interstate or
    foreign commerce by any means, including by computer.”
    To sustain its burden of proof for the crime of
    receiving child pornography, the government must prove
    the following essential elements beyond a reasonable
    doubt.
    One, that the defendant did knowingly receive
    computer files or any other material that contained
    child pornography.
    And two, that such material of child pornography
    had   been   mailed  or  shipped   or  transported   in
    interstate or foreign commerce by any means, including
    by computer.
    And three, that at the time of such receipt of
    child pornography, the defendant believed that such
    (Continued)
    11
    beginning deliberations, the jury was provided a written copy of
    the court’s instructions.
    The   following   day,    the     jury   sent   a   note    to   the   court,
    asking “[i]f the defendant is aware of ‘another’ person doing
    the act of ‘knowingly receiving,’ does it read on the defendant
    Thomas Yu unlawfully and knowingly receiving.”                   J.A. 758.      At
    about   4:00   pm,   the    district    court   convened        the   parties   to
    discuss a response.        After hearing from both sides, the district
    court proposed the following answer:
    Concerning receipt of child pornography Count Two, the
    essential elements of this offense are in Instruction
    16.     You may want to re-read Instruction 16.
    Additionally, mere knowledge that a crime is or has
    been   committed   does   not  constitute   “knowingly
    receiving.” In further response to your question, the
    Government must prove that the defendant was aware
    material constituted or contained child pornography as
    defined further in these instructions.
    With respect to Count II of the indictment, the
    government is only required to prove that the
    defendant knowingly received a single image. However,
    you have to be unanimous with respect to the image or
    images   of  child   pornography  you   determine  were
    received by--by the defendant for that count.
    Therefore, with respect to Count II as long as
    you find beyond a reasonable doubt that the defendant
    knowingly received a single image and that the other
    elements of the offense have been proved beyond a
    reasonable doubt, you must find the defendant guilty.
    J.A. 641-42.    Yu has not challenged the propriety of this
    instruction, nor has he argued that the court’s original written
    instruction as to Count II--which was not included in the record
    on appeal--was erroneous.
    12
    that child pornography was on his computer and he--the
    defendant knowingly received it with the intent to
    control it.     (E.g. view it or store it for later
    viewing by the defendant or someone else). If someone
    other   than   the   defendant   downloaded   the  child
    pornography   and   the   defendant   was   aware  child
    pornography was placed on his computer and the
    defendant intended to or did exercise control over it
    then the defendant has received child pornography.
    J.A. 741-42, 759. 7
    Defense    counsel    objected      to    the   last   sentence   of   the
    court’s response, arguing that it “propose[d] hypothetical facts
    that the jury[]” would “take and apply to this case that weren’t
    presented in evidence.”          J.A. 735.     The district court rejected
    defense counsel’s argument and submitted the instruction to the
    jury as drafted.         It simultaneously sent word to the jury to
    return to the courtroom to be dismissed through the weekend. 8
    In light of the pending gap in the jury’s deliberations,
    defense counsel requested the opportunity to file a motion on
    the disputed instruction.         The district court consented, and, on
    February 6, Yu filed his “motion to modify answer to jury’s
    question,”     arguing    that    the   last    sentence    of   the   district
    7
    The record only contains a revised jury instruction, which
    did not include the initial instruction’s disputed final
    sentence. We have included the language of that sentence as it
    appeared in Yu’s motion to amend the original instruction. The
    government has not challenged the accuracy of that language.
    8
    Although February 5, 2009 was a Thursday, the court had
    earlier advised the jury that court would not be in session on
    Friday.
    13
    court’s      supplemental        instruction         conflated     receipt       of    child
    pornography with mere possession of child pornography.                                  J.A.
    741.
    The court reconvened on February 9.                    After hearing argument
    from both parties on the merits of Yu’s motion, the district
    court,      without    conceding        error,      offered   to   “delete       the       last
    sentence entirely.”             J.A. 749.        Defense counsel agreed that the
    alteration would address Yu’s concerns and asked the court to
    deliver the revised instruction orally.                       Noting that the jury
    had been given the original supplemental instruction “for less
    than    five       minutes,”     before       the    court    “took    it    back,”        the
    district court instead opted to give the jury the updated answer
    in   writing,       with    a   note     on   it    indicating     that     it   had       been
    revised.       J.A. 749-50.         The revised instruction was dispatched
    just before 10:00 am.             About one hour later the jury returned a
    guilty verdict on all three counts.
    On    May     28,    2009,      the    district     court     sentenced        Yu    to
    concurrent      terms      of   eighty-four         months’   imprisonment        on       each
    count of conviction, to be followed by seven years of supervised
    release.      This appeal followed.
    II.
    On    appeal,       Yu   argues    that      the   district    court      committed
    reversible error by: (1) limiting his cross-examination of the
    14
    government’s forensic expert, (2) precluding a defense witness
    from testifying, and (3) providing the jury with a response that
    broadened the theory on which he could be found guilty and then
    delivering a corrective instruction in writing rather than in
    open court.     We review the alleged violations in turn.
    A.
    Yu objects to the district court’s handling of his cross-
    examination     of   Agent   Mizell,     who   testified        as   a   government
    forensic computer expert.        Yu makes two arguments: (1) that the
    district court “precluded an entire line of cross-examination
    directed at errors and/or bias inherent in Mizell’s forensic
    analysis,” Appellant’s Br. at 25, and (2) that “the district
    court    erroneously   prevented       [him]   from   attempting         to    refresh
    Mizell’s recollection,” id.
    Although the Sixth Amendment affords defendants the right
    to confront witnesses against them, trial courts enjoy “wide
    latitude insofar as the Confrontation Clause is concerned to
    impose reasonable limits on . . . cross-examination.”                           United
    States v. Ambers, 
    85 F.3d 173
    , 176 (4th Cir. 1996) (quoting
    Delaware v. Van Arsdall, 
    475 U.S. 673
    , 679 (1986)); see also
    United States v. Ayala, 
    601 F.3d 256
    , 273 (4th Cir. 2010).                          We
    review    the   district     court’s    restrictions       on    Agent        Mizell’s
    cross-examination      for   abuse     of    discretion,    United       States    v.
    Scheetz, 
    293 F.3d 175
    , 184 (4th Cir. 2002), and find none.
    15
    Yu’s first argument is utterly unsupported by the record.
    As    described      above,     the    transcript     of     Agent         Mizell’s    cross-
    examination is replete with instances in which Mizell confirmed
    that    he   could    not     verify     whether      Yu    had       in   fact    uploaded,
    downloaded, or viewed images of child pornography.                            Agent Mizell
    also acknowledged that he had presented a selective sample of
    the    available     data,      conceded     that    he    had    culled       the    browser
    histories with an eye toward developing the case against Yu, and
    noted his failure to investigate other potential users of the
    seized computers.          Agent Mizell could scarcely have been clearer
    on these points.             In short, defense counsel was given broad
    latitude to question Agent Mizell about potential errors and
    biases and duly availed himself of the opportunity to do so.
    Yu’s    claim      that   the    district     court       precluded         inquiries     into
    these subjects lacks merit.
    To    the    extent      that   Yu    challenges       the      district       court’s
    restriction of questions that relied on the raw data prepared by
    the defense, his argument fails.                    It is a fundamental rule of
    evidence      that    authentication          or    identification            of     physical
    evidence      is     “a   condition         precedent      to     admissibility”          and
    requires     “evidence       sufficient       to    support       a    finding     that   the
    matter in question is what its proponent claims.”                            Fed. R. Evid.
    901(a); see also United States v. Jones, 
    356 F.3d 529
    , 535 (4th
    Cir. 2004).         Here, the district court found that because Agent
    16
    Mizell       had    no    way       of   knowing        if     Yu’s        raw    data    accurately
    reflected the material from which Mizell had worked, there was
    not     a    proper       foundation            for     use     of       the     data     in    cross-
    examination.          This determination was not an abuse of the court’s
    discretion.           See      Ayala,      
    601 F.3d at 272-73
           (holding       that    a
    district court did not abuse its discretion by requiring defense
    counsel “to abide by . . . elementary [evidentiary] precepts”
    during       cross-examination             “to        ensure        that    the    jury        was    not
    misled”).
    By      the   same        token,     the        district       court       did     not    err    by
    refusing to allow defense counsel to “refresh” Agent Mizell’s
    recollections            of     his      earlier        analysis           by    referencing          the
    defense’s       raw      data.           “The    matter        of     refreshing         a     witness’
    recollection          and       the      manner        used        are     largely       within       the
    discretion of the Trial Judge.”                         United States v. Cranson, 
    453 F.2d 123
    , 124 (4th Cir. 1971); see also Charles Wright & Victor
    Gold, 28 Federal Practice & Procedure: Evidence § 6184, at 458-
    59 (1993).          As Agent Mizell did not know if the document at
    issue       contained         the   same    data       he     had    reviewed,         the     district
    court could easily have determined that he could not have had
    his recollection accurately refreshed by reviewing it.
    B.
    Yu next challenges the district court’s refusal to allow
    Tami Loehrs to testify as a lay witness.                                 We review the district
    17
    court’s choice of Rule 16 sanctions for abuse of discretion.
    United States v. Fletcher, 
    74 F.3d 49
    , 54 (4th Cir. 1996).                            Yu
    acknowledges that his disclosure of Loehrs’s expert testimony
    was untimely and concedes that the district court was within its
    discretion to exclude Loehrs as an expert.                     Appellant’s Br. at
    36-37.     However, he renews his claim that Loehrs was slated to
    testify as a lay witness and asserts that the exclusion of her
    lay testimony was an abuse of discretion.                 Yu’s argument fails.
    The    Federal    Rules    of    Evidence     draw    a   clear     distinction
    between    “lay”    testimony,       governed    by   Rule     701,    and     “expert”
    testimony, governed by Rule 702, to avoid “the risk that the
    reliability requirements set forth in Rule 702 will be evaded
    through    the    simple    expedient    of     proffering     an     expert    in   lay
    witness clothing.”          Fed. R. Evid. 701(c), advisory committee’s
    note to 2000 Amendments; see also Fed. R. Evid. 702 (describing
    expert testimony as that requiring “scientific, technical, or
    other specialized knowledge”); Fed. R. Evid. 701(c) (proscribing
    lay testimony “based on . . . knowledge within the scope of Rule
    702”).     Yu’s effort to recast Loehrs as a lay witness suggests
    just such an evasion.
    Even    if    defense    counsel     accurately       represented         Loehrs’s
    testimony as going only to the “chain of custody” of data she
    extracted    from     the    seized     computers,     such      testimony        would
    inevitably have implicated expert knowledge within the scope of
    18
    Rule    702.      Agent   Mizell’s        testimony      about    data     recovery
    illustrates     the   point.        During       cross-examination        of    Agent
    Mizell, defense counsel elicited an explanation of the technique
    forensic examiners typically use to extract data.                   Agent Mizell
    confirmed that forensic examiners typically use software called
    “EnCase”   to   remove    data,     after      which   they   translate    the   raw
    information into a viewable format.
    As Agent Mizell’s testimony shows, the process of forensic
    data extraction requires “some specialized knowledge or skill or
    education that is not in possession of the jurors.”                            United
    States v. Johnson, 
    617 F.3d 286
    , 293 (4th Cir. 2010) (quoting
    Certain Underwriters at Lloyd’s, London v. Sinkovich, 
    232 F.3d 200
    , 203 (4th Cir. 2000) (internal quotations omitted)); see
    also United States v. Ganier, 
    468 F.3d 920
    , 926 (6th Cir. 2006)
    (holding that testimony that would “require [the witness] to
    apply    knowledge     and     familiarity        with       computers    and    the
    particular forensic software well beyond that of the average
    layperson” fell within the scope of Rule 702).                   In other words,
    even if Loehrs had confined her testimony to her extraction and
    translation of the data at issue, she would not have offered lay
    opinion.       Yu’s assertions to the contrary strain credulity--
    particularly     in   light    of   the     summary     of    Loehrs’s    testimony
    contained in Yu’s Rule 16 notice and defense counsel’s explicit
    19
    reference to Loehrs as “the expert . . . in the courtroom today”
    during his cross-examination of Agent Mizell.                 J.A. 303.
    We have explicitly rejected attempts to make an end-run
    around the Federal Rules of Evidence by blurring the distinction
    between expert and lay testimony.             See Johnson, 
    617 F.3d at 293
    .
    The district court did not abuse its discretion by preventing
    such an effort here.
    C.
    Finally, Yu argues that the district court committed error
    with respect to its jury instructions.               He urges in particular
    that the district court impermissibly broadened the theory on
    which he could be convicted of receipt of child pornography when
    responding to a question from the jury.                  Although he concedes
    that the deletion of the disputed sentence adequately addressed
    the alleged error, he claims that the district court’s failure
    to provide the revision orally violated his right under Federal
    Rule of Criminal Procedure 43 to be present at “every trial
    stage.”      Fed.    R.    Crim.   P.   43(a)(2).        We    review     preserved
    challenges   to     jury   instructions      as   well   as    alleged     Rule   43
    violations for harmless error.               United States v. Jeffers, 
    570 F.3d 557
    , 564 n.4 (4th Cir. 2009); United States v. Pratt, 
    351 F.3d 131
    , 138 (4th Cir. 2003).
    Yu claims that the final sentence in the district court’s
    initial   response    to    the    jury’s    question    allowed   the     jury   to
    20
    convict him for receipt of child pornography on a theory of mere
    possession.        Even if that were so, any error was harmless.                The
    jury   had   the    disputed   instruction      for    a   brief    period    before
    being dismissed for a long weekend.                  When court reconvened on
    Monday morning, the jury was promptly provided with a revised
    instruction    the     substance   of        which    Yu   expressly    approved.
    Deliberations proceeded for an hour before the jury reached its
    verdict.      On these facts, we do not see how the challenged
    instruction could have affected the outcome.
    Any Rule 43 error was similarly harmless.                   Neither Yu nor
    his attorney were excluded from any part of the district court’s
    consideration of the jury’s question or the preparation of the
    court’s reply.        Cf. United States v. Rhodes, 
    32 F.3d 867
    , 874
    (4th Cir. 1994).        To the contrary, both Yu and his counsel were
    informed of the jury’s question, provided extensive input into
    the    district      court’s    revised       response,      were     aware    what
    instruction the jury was being given, and explicitly endorsed
    the contents of the corrected instruction. 9               Once again, there is
    9
    At oral argument, Yu noted that the record does not
    confirm whether the corrective note was ever received by the
    jury.   Although it would certainly have been better if the
    district court had created a clear record by delivering the
    instruction orally, absent any indication that the note was not
    properly delivered by the officer of the court to whom it was
    entrusted, we assume that it was.   See United States v. Pratt,
    
    351 F.3d 131
    , 138 (4th Cir. 2003).
    21
    simply “no reasonable possibility that the practice complained
    of might have contributed to the conviction.”    Pratt, 
    351 F.3d at 138
     (internal quotations omitted); see also United States v.
    Solomon, 
    565 F.2d 364
    , 366 (5th Cir. 1978) (finding no prejudice
    from submission of supplemental instruction to jury in writing
    rather than orally).
    III.
    For the foregoing reasons we affirm Yu’s conviction.
    AFFIRMED
    22