People v. Cardona CA4/1 ( 2023 )


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  • Filed 4/14/23 P. v. Cardona CA4/1
    NOT TO BE PUBLISHED IN OFFICIAL REPORTS
    California Rules of Court, rule 8.1115(a), prohibits courts and parties from citing or relying on opinions not certified for
    publication or ordered published, except as specified by rule 8.1115(b). This opinion has not been certified for publication
    or ordered published for purposes of rule 8.1115.
    COURT OF APPEAL, FOURTH APPELLATE DISTRICT
    DIVISION ONE
    STATE OF CALIFORNIA
    THE PEOPLE,                                                          D079256
    Plaintiff and Respondent,
    v.                                                         (Super. Ct. No. SCN389414)
    JOEL CARDONA,
    Defendant and Appellant.
    APPEAL from a judgment of the Superior Court of San Diego County,
    Brad A. Weinreb, Judge. Affirmed.
    Joanna McKim, under appointment by the Court of Appeal, for
    Defendant and Appellant.
    Rob Bonta, Attorney General, Lance E. Winters, Chief Assistant
    Attorney General, Charles C. Ragland, Assistant Attorney General,
    A. Natasha Cortina, Christine Levingston Bergman, and Kathryn
    Kirschbaum, Deputy Attorneys General, for Plaintiff and Respondent.
    A jury found Joel Cardona guilty of second-degree murder as a lesser
    included offense of first-degree murder. (Pen. Code, § 187, subd. (a),
    count 1.)1 The trial court subsequently made true findings on allegations of a
    prior strike conviction and prior serious felony conviction. (§§ 1170.12, subds.
    (a)-(d), 667, subds. (a)(1) & (b)-(i).) The court declined to strike either of the
    prior conviction enhancements and sentenced Cardona to 30 years to life,
    plus five years.
    Cardona contends on appeal that: (1) the trial court violated his
    constitutional rights by not suspending proceedings under section 1368 to
    conduct a third competency hearing; (2) the court prejudicially erred in
    failing to instruct the jury on voluntary manslaughter based on imperfect
    self-defense (CALCRIM No. 571) and mental impairment (CALCRIM
    No. 3428); (3) the court prejudicially erred in finding that Cardona waived his
    Miranda2 rights and admitting his post-arrest statements; and (4) there was
    insufficient evidence to support the jury’s finding of guilt for second-degree
    murder.
    We conclude that the trial court did not abuse its discretion in
    refraining from suspending proceedings to conduct another competency
    hearing. We also conclude that the evidence did not warrant instructing the
    jury on either imperfect self-defense or mental impairment, and any error in
    declining to do so was harmless. We reject Cardona’s argument that the trial
    court prejudicially erred in admitting Cardona’s post-arrest statements,
    because he impliedly waived his Miranda rights. Finally, viewing the
    evidence in the light most favorable to the jury verdict, we conclude that
    there is substantial evidence to support the jury’s finding that Cardona acted
    1     Further statutory references are to the Penal Code unless otherwise
    stated.
    2     Miranda v. Arizona (1966) 
    384 U.S. 436
     (Miranda).
    2
    with implied malice, and that his acts were a substantial factor in causing
    the victim’s death. Accordingly, we affirm.
    FACTUAL AND PROCEDURAL BACKGROUND
    A. N.J.’s Killing
    In August 2018, the victim, N.J., was living with his uncles Rafael J.
    and Mauricio J. at their house in Oceanside. Cardona, a cousin in the family,
    went to their house on August 1, 2018. Mauricio had taken Cardona to the
    hospital earlier that day after he fell and cut his eyebrow, for which doctors
    gave him stitches and prescribed pain medication. That evening, Cardona
    spent all night awake watching sports, even though his family members told
    him to “take [his] meds and go to sleep.”
    The following morning on August 2, 2018, sometime after 6:00 a.m.,
    Rafael prepared to leave for work in his truck. But Cardona was nervous and
    tried to keep Rafael from leaving. Rafael asked N.J. to call 911 because
    Cardona “was not well” and was using foul language to confront Rafael. A
    responding officer arrived around 6:47 a.m., spoke briefly with Rafael before
    he left for work, and then talked with Cardona, who was evasive at first.
    However, after the officer was able to obtain Cardona’s information and
    determine there were no outstanding warrants for his arrest, the officer
    advised Cardona to avoid further conflict and left the residence around
    7:05 a.m.
    Less than 15 minutes later, a neighbor, Vanessa Q., called 911 to report
    that Cardona and N.J. were fighting in the front yard of Rafael’s house.
    Vanessa, while staying on the phone with the 911 dispatcher, walked towards
    the yard and saw N.J. face down on the ground with his shirt over his face.
    Cardona was on top of N.J. with one knee on his back, punching N.J. in the
    head. N.J. pled for help and Vanessa heard N.J. say to Cardona, “You’re
    3
    going to kill me.” She also recalled Cardona saying “remember my sister” as
    he hit N.J. Vanessa told Cardona to stop, but he continued to punch N.J.
    around his head and face. When Vanessa got closer, Cardona told her to “get
    back” because “you’re ugly.” Around that time, Vanessa noticed that N.J.
    was no longer talking and appeared to be unconscious. She told Cardona,
    “Stop, you’re go[ing to] kill him. Stop it. Please.” She then screamed for
    Cardona to stop, telling him again, “You’re killing him[!]” Vanessa’s 911 call,
    which was recorded, lasted approximately ten minutes.
    Vanessa testified at trial that Cardona remained on top of N.J. the
    entire time she observed the incident and hit him “nonstop.” She never saw
    N.J. change positions, hit or kick Cardona, or fight back. She also described
    how, while N.J.’s shirt was over his face, she could see the shirt moving in
    and out of his mouth as he was breathing and screaming.
    The same officer who came to the residence earlier that morning was
    the first to respond to the fight. When he arrived at 7:21 a.m., he saw
    Cardona “smashing” N.J.’s face into the roots of a tree in the yard. The
    officer drew his firearm and yelled at Cardona, “Let him go or I’m going to
    fucking shoot you[!]” The officer testified that Cardona looked at him,
    reached under N.J.’s neck, and pulled it back with “a significant amount of
    force” in a “snapping-like motion.” N.J.’s head then fell forward quickly and
    hit the ground hard, after which his body went limp. Vanessa also testified
    that when the officer arrived at the scene, she saw Cardona pull N.J.’s neck
    and torso back with his left arm before dropping N.J. to the ground, after
    which N.J. stopped moving.
    Cardona then leaned forward towards the officer, who realized that
    Cardona was unarmed. The officer holstered his firearm and tasered
    Cardona instead. The officer ordered him to get on the ground, but Cardona
    4
    still did not comply and instead tried to remove the taser prongs from his
    body. The officer deployed his taser again, but to no avail. After he was
    tased three more times, Cardona eventually complied, and the officer
    proceeded to handcuff him.
    The officer turned to N.J., who was not moving or breathing, and
    attempted to render aid. But while the officer administered CPR, Cardona
    began kicking the officer in his lower back and trying to kick N.J. in the head.
    Cardona tried to get up while still handcuffed, so the officer stopped
    rendering aid to N.J. and restrained Cardona further until other officers
    arrived at the scene. When they arrived, Cardona was tased two more times
    because he continued to struggle and attempt to kick N.J.’s head. Cardona
    was ultimately placed in a full-body harness to restrain his movement, N.J.
    was declared dead at the scene.
    A field evidence technician processed the crime scene and noted that
    the dining room inside the house was in disarray. Chairs and the trash can
    were knocked over, the television was lying on the living room floor, and the
    technician found blood drops on the kitchen floor. Testing showed that the
    blood came from N.J. and not Cardona.
    N.J.’s uncles testified that N.J. had been living at their house for years,
    and they never saw Cardona and N.J. argue, nor were they aware of any
    problems between the two. Rafael also testified that Cardona’s behavior that
    morning was strange and out of character, but N.J. was acting normal and
    sitting on his bed resting when Rafael asked him to call the police.
    B. Cardona’s Post-Arrest Interrogation
    Two detectives attempted to speak with Cardona on the day of the
    incident after he was taken to a hospital for treatment, but he had trouble
    staying awake due to sedatives he was given. Instead, the detectives
    5
    questioned Cardona in jail the following day on August 3, 2018. At that time,
    Cardona appeared alert, engaged, and interested in speaking with them.
    One detective advised Cardona of his Miranda rights, and Cardona verbally
    confirmed that he understood them. The detectives did not expressly ask
    Cardona if he was willing to waive his rights and speak to them, but Cardona
    proceeded to answer questions about the previous day’s events.
    Cardona told the detectives that after Mauricio took him to the hospital
    to get stitches for his eyebrow, he went back to his cousins’ house and stayed
    up all night watching sports. The following morning, he went outside and
    tried to keep his cousin Rafael from going to work because he was feeling
    paranoid and was afraid of being alone at the house.
    After he spoke with the officer who was dispatched to the house,
    Cardona went inside and saw N.J. in the kitchen. Cardona said that N.J.
    made a comment about the oven being his, which angered Cardona because
    the house belonged to N.J.’s uncles, and he thought N.J. was being
    disrespectful. Cardona punched N.J. in the mouth, N.J. responded by
    pushing Cardona in the chest, and the two brawled inside before eventually
    moving to the front yard.
    When they were fighting outside, Cardona remembered that he had
    seen N.J. wearing sunglasses that Cardona thought were his, and it made
    him angry that N.J. may have stolen the sunglasses from Cardona’s sister’s
    car. Cardona said he asked N.J. where his sunglasses were while he was
    hitting him, and that he had his knee on N.J.’s back. When N.J. did not
    answer, Cardona continued to punch him. Cardona told detectives that he
    only hit N.J. a few times, and that he stayed on top of him because “. . . I
    didn’t know if [N.J.] was going to grab me and like try to take advantage of
    me to where I was in a position to defend myself.” Cardona did not recall
    6
    N.J. telling him to stop or telling him that he was killing him, and Cardona
    said “. . . I would’ve stopped if, if I knew that was the—that’s what he was
    saying.” Cardona said that he did not intend to kill N.J., and that he did not
    remember hitting N.J.’s head against tree roots in the front yard. However,
    Cardona did recall N.J. yelling for him to get back, and he remembered
    Vanessa coming over to say, “stop, you’re killing him.”
    When asked why he would react so strongly to N.J. saying the oven was
    his, or N.J. taking his sunglasses, Cardona said, “Probably because I spent
    the whole night up” and “I don’t know.” According to Cardona, he had a good
    relationship with N.J., and they had never fought before or had any issues in
    the past. When asked whether he could have walked away from the
    altercation after N.J. was face down and Cardona had the position of
    advantage, he agreed that he could have chosen to get off N.J.—but he
    continued to hit N.J. because he was “waiting for an answer” regarding his
    sunglasses. Cardona made no mention of N.J. threatening him or using a
    weapon against him.
    C. Medical Examiner’s Testimony
    A medical examiner testified regarding her inspection of N.J.’s body.
    She observed bruising and abrasions on his face, neck, chest, abdomen, and
    back. She found lacerations on his scalp and small hemorrhages on his
    eyelids, which could be consistent with strangulation or a violent cough.
    There were also tears and bleeding inside N.J.’s mouth.
    As for internal injuries, there was bleeding under N.J.’s scalp on the
    front, sides, and back of his head, with a small subdural hemorrhage along
    the base of his brain. Those internal injuries were hallmarks of force applied
    to the brain, and Cardona’s external injuries were also consistent with him
    being punched in the head and face repeatedly. There were hemorrhages on
    7
    both sides of N.J.’s neck, which were consistent with being held in a
    chokehold for several minutes and being yanked backwards by the neck.
    Injuries on N.J.’s torso and back were also consistent with him being pinned
    face down to the ground with someone sitting on his back.
    A toxicology test detected the presence of methamphetamine in N.J.’s
    blood at 0.92 milligrams per liter, a concentration slightly below the average
    level of fatal overdoses seen in the medical examiner’s office. The medical
    examiner concluded that the cause of death was “head and neck trauma with
    methamphetamine toxicity contributing,” and that the manner of death was
    homicide. Multiple factors could have played a role in N.J.’s death, including
    blunt force trauma to N.J.’s head, strangulation from having an arm around
    his neck, suffocation from his shirt against his nose and mouth, mechanical
    asphyxia from someone sitting on his back, and the effects of
    methamphetamine in his system. However, there was no way to single out
    any of the factors as the cause of death. While the level of methamphetamine
    in N.J.’s blood could have caused an overdose or increased his risk of fatal
    cardiac arrest, N.J. also could have survived if not for his other injuries.
    D. Toxicologists’ Testimony
    The defense called Dr. Charles O’Connell, a medical toxicologist, as an
    expert witness. In his opinion, N.J.’s individual injuries were not
    independently fatal. The 0.92 milligrams per liter concentration of
    methamphetamine found in N.J.’s blood was “relatively high” and within
    overdose range, but sometimes the concentration of methamphetamine
    detected after death is higher than pre-mortem levels. Inexperienced users
    could have a more extreme response to methamphetamine than more
    frequent users, who have a higher tolerance. Such responses could include
    cardiac arrest or arrhythmias, which would be exacerbated by a physical
    8
    altercation or having another person’s weight on top of them. When asked
    whether it was possible for someone like N.J. to survive his injuries from the
    fight with Cardona, absent methamphetamine, Dr. O’Connell said it was
    possible. He also said that a person “being . . . choked [while] their head is
    being . . . hit into the ground . . . is potentially fatal if it goes on long enough.”
    The People called Dr. Ola Bawardi, a forensic toxicologist, as a rebuttal
    expert witness. She testified that physical symptoms of methamphetamine
    use include hyperactivity, rapid speech, and fidgeting. While the
    concentration of methamphetamine in N.J.’s blood was high, post-mortem
    redistribution of methamphetamine can cause a “false elevation of the level of
    methamphetamine that a person would have had at the time of death[.]”
    Given his detected blood concentration level, Dr. Bawardi believed that N.J.
    had used methamphetamine within 12 hours of his death.
    E. 911 Dispatcher Testimony
    The People called as a rebuttal witness the 911 dispatcher who took
    N.J.’s call when Cardona was preventing Rafael from leaving for work. After
    the People played the call recording, which lasted approximately five
    minutes, the dispatcher testified that N.J. seemed “very calm [and]
    forthcoming answering questions in a cohesive manner.” She described N.J.’s
    demeanor on the call as “calm” and “factual.”
    F. Verdict and Sentencing
    The People charged Cardona with murder and alleged a serious felony
    prior and a strike prior. (§ 187, subd. (a), count 1; §§ 1170.12, subds. (a)-(d),
    667, subds. (a)(1) & (b)-(i)).
    After the jury began deliberating, it requested a readback of the
    testimony from the responding officer and one of the detectives who
    interrogated Cardona. The jury also asked for clarification of CALCRIM
    9
    No. 520, the instruction on first- or second-degree murder with malice
    aforethought, and more specifically, the meaning of “at the time he acted, he
    knew his act was dangerous to human life.” The jury’s note said that “some
    of us interpret that as affecting life such as harmed, disabled, or
    marred[/]crippled” and “others interpret [that] as causing death or taking a
    human life. Any further clarification that you can offer on this element of
    first/second degree murder would be appreciated.” After hearing from the
    parties, the court responded to the jury with the following: “The risk of
    serious bodily injury alone is not sufficient. There must be awareness of the
    risk of death from the defendant’s actions.”
    The jury subsequently found Cardona guilty of second-degree murder
    as a lesser included offense of first-degree murder. (§ 187, subd. (a), count 1.)
    After Cardona waived his right to have the jury decide the prior conviction
    allegations, the trial court made true findings on the allegations of a prior
    strike conviction and prior serious felony conviction. (§§ 1170.12, subds. (a)-
    (d), 667, subds. (a)(1) & (b)-(i).) In June 2021, the trial court declined to
    strike either of the prior conviction enhancements and sentenced Cardona to
    30 years to life plus five years.
    DISCUSSION
    I
    Cardona first contends that the trial court had an obligation to suspend
    proceedings under section 13683 to conduct another competency hearing,
    3     Section 1368 provides, in relevant part:
    10
    even though two different psychiatrists had already conducted pretrial
    evaluations within the year before trial and found him competent. We
    conclude that the trial court did not abuse its discretion in refraining from
    suspending proceedings because the record does not show that circumstances
    had substantially changed in a manner casting doubt on the validity of the
    two prior competency findings.
    We begin first with additional background information relevant to this
    issue before setting forth the governing legal principles and explaining our
    conclusion.
    A. Additional Relevant Facts
    In January 2019, a year before Cardona’s trial commenced, the court
    suspended proceedings pursuant to section 1368 so that he could undergo a
    “(a) If, during the pendency of an action and prior to judgment . . . a
    doubt arises in the mind of the judge as to the mental competence of the
    defendant, he or she shall state that doubt in the record and inquire of the
    attorney for the defendant whether, in the opinion of the attorney, the
    defendant is mentally competent. . . . At the request of the defendant or his
    or her counsel or upon its own motion, the court shall recess the proceedings
    for as long as may be reasonably necessary to permit counsel to confer with
    the defendant and to form an opinion as to the mental competence of the
    defendant at that point in time.
    “(b) If counsel informs the court that he or she believes the defendant is
    or may be mentally incompetent, the court shall order that the question of
    the defendant’s mental competence is to be determined in a hearing which is
    held pursuant to Sections 1368.1 and 1369. If counsel informs the court that
    he or she believes the defendant is mentally competent, the court may
    nevertheless order a hearing. Any hearing shall be held in the superior
    court.
    “(c) Except as provided in Section 1368.1, when an order for a hearing
    into the present mental competence of the defendant has been issued, all
    proceedings in the criminal prosecution shall be suspended until the question
    of the present mental competence of the defendant has been determined.”
    11
    competency examination. In March 2019, a psychiatrist determined that
    Cardona was competent to stand trial after interviewing him in custody and
    reviewing his case records. The psychiatrist noted that Cardona had a self-
    reported history of schizoaffective disorder. Cardona also told the
    psychiatrist that he was not taking any mental health medications at the
    time of the interview but had received treatment at a hospital and taken
    medications in the past. The psychiatrist observed that Cardona “did not
    want to sit down for the interview and wanted to stand,” that he did not
    always answer questions directly, and that he would “ramble at times.”
    However, the psychiatrist also observed that Cardona had no active
    symptoms of schizoaffective disorder and concluded that Cardona had “the
    ability to understand the nature of the proceedings against him[]” and
    “cooperate with his attorney in a rational manner in his own defense.”
    In June 2019, the court suspended proceedings again pursuant to
    section 1368 because Cardona’s attorney declared doubts about his
    competency. A different psychiatrist evaluated Cardona, and in July 2019 he
    also found Cardona competent to stand trial. The psychiatrist noted that
    during the interview, Cardona “fluctuated in his cooperation” with answering
    questions, but “was oriented and did not display any psychotic symptoms . . .”
    Cardona “showed difficulty with remaining focused” and “frequently changed
    the subject of questions asked,” going on “short tangents questioning his own
    willingness to cooperate with the evaluation, before eventually deciding to
    continue.” Cardona again reported being hospitalized and diagnosed with
    schizoaffective disorder in the past. However, Cardona said he was not under
    the care of a jail psychiatrist at the time of the interview and was not taking
    any psychiatric medications because they “weigh him down.” The
    psychiatrist concluded, as the previous psychiatrist had, that despite
    12
    Cardona’s deficits in focus and intellectual functioning, he had “no
    diagnosable severe mental illness” and “appear[ed] capable of assisting his
    attorney in a rational defense[.]”
    Proceedings were reinstated and pretrial motions were heard in early
    January 2020. During that hearing, the trial court noted that it had spoken
    with Cardona about appropriate courtroom behavior and found that
    restraints were not necessary at that time. The court thanked Cardona for
    being respectful of the process that morning, and the following exchange
    ensued:
    “[CARDONA]: Go into your afternoon.
    “THE COURT: I’m sorry?
    “[CARDONA]: Into your late afternoon, into your late
    evening, into your night.
    “THE COURT: Thank you. The court is aware–
    “[CARDONA]: Can I address the court?
    “THE COURT: One second, please. The court – the court’s
    aware of the legal evidentiary requirements that [the] court
    must engage in prior to engaging in restraints. There’s
    nothing before me that would suggest the need to do [so]
    now. If an issue comes to the court’s attention that we need
    to address, we’ll do so at the appropriate time.”
    Early on the first day of trial on January 7, 2020, the following
    exchange occurred outside the presence of the jury:
    “THE COURT: . . . I want to caution you, you’ve stood up a
    couple of times today and yesterday. It makes my bailiff
    nervous when you do so and when it’s happening as a
    surprise. [¶] And so–
    “[CARDONA]: Okay. Okay. I apologize. I won’t–
    “THE COURT: And I–
    “[CARDONA]: Do my best to refrain from that. Thank you
    so much.
    “THE COURT: I appreciate that. It’s – It’s also for your
    safety as well. So–
    “[CARDONA]: I understand. Like, I already know the
    repercussions. Like–
    13
    “THE COURT: That’s fine.
    “[CARDONA]: All, like, duration of time.
    “THE COURT: I appreciate that. We’re here for a long
    time, and sometimes we all need to stand up and stretch,
    and sometimes we need to take breaks. [¶] If you need to
    take a break other than when we have the scheduled
    breaks, you let your attorney know. . . . But in terms of you
    interacting with the jurors, interacting with members of
    the public or family members that may be in the courtroom,
    I’m going to ask you not to do so.
    “[CARDONA]: Okay.”
    Soon thereafter, before opening statements, the court admonished Cardona
    that if necessary, the court would consider using a chair with restraints to
    prevent him from standing up.
    Later that afternoon, the court noted that Cardona had stood up
    “several times” and that Cardona reached forward and grabbed his name
    plate twice. Cardona, talking over the court at times, said, “You have to
    excuse me . . . I was in college, you know, I got a lot of racing thoughts and
    stuff like that . . . You know, I don’t mean any harm . . . I don’t even recall,
    like, what’s going on[.] . . . I’m not a mess-up. I’m not a fuck up.” The court
    stated that reaching for the name plate caused security concerns, so the name
    plate was removed from the table. The court also noted that Cardona was
    “becoming frustrated with this process[,]” and that the court had given
    Cardona the opportunity to speak with his attorney. This exchange then
    ensued:
    “[CARDONA]: You can excuse my language, you know.
    “THE COURT: You – You’ve been respectful of the process,
    but you have not been conforming with some of the things
    that I’ve asked you to do. [¶] I don’t want you standing up
    anymore during the trial.
    “[CARDONA]: That’s fine. That’s fine.
    “THE COURT: And we may have – If you’re not able to
    conform with my rulings, we may have to take additional
    14
    measures such as securing you to the chair. But I’m going
    to give your attorney the opportunity to talk to you–
    “[CARDONA]: Put me back in the cell. He’ll [defense
    counsel] fight my case.”
    After Cardona stood again before a witness took the stand, the court
    recessed for Cardona to speak with his attorney about potentially being
    restrained. After the recess, Cardona’s attorney objected to using a restraint
    chair because of how the jury would perceive it. The court noted that the jury
    would not be able to see that he was being restrained, the chair would still
    allow him to have free movement of his upper body, and it would not infringe
    on his ability to assist his counsel. As the court was making these
    statements, Cardona asked, “What if it had suicide doors?” He and the court
    then engaged in cross-talk, during which Cardona said, “I was abiding by the
    laws enacted, you know, like, in 2017, ’18, ’19. So . . . I have nothing to say.”
    The court admonished Cardona not to speak while it made its ruling.
    The court’s bailiff then spoke on the record about Cardona’s repeated
    non-compliance with instructions to remain seated, as well as about jail
    records indicating he “hasn’t been compliant with his medication[.]” After
    hearing those comments, the court found that there was a need for Cardona
    to use the restraint chair for security reasons. The court also stated that it
    did not “have any issues or concerns with respect to [section] 1368 or
    competency issues[]” and it believed Cardona was being impacted by the
    “emotional nature of . . . the case.” The court admonished Cardona that if he
    continued to be disruptive, it could remove him from the courtroom, or
    Cardona could choose not to participate in the proceedings.
    When trial adjourned for the day and the attorneys were addressing
    the admissibility of Cardona’s post-arrest statements, Cardona interrupted
    twice: once to mention “1982,” and once to ask, “Are we having pizza[?]” At
    15
    his attorney’s request, the court made “another referral to jail medical to
    evaluate and address” Cardona’s “medication issues[.]”
    The second day of trial proceeded without incident, but on the third
    day, Cardona interjected a few times while the attorneys discussed jury
    instructions with the court. At one point he asked, “You guys seen that
    movie Marshal?” As the discussion progressed, Cardona asked to leave and
    said, “I have small claims court handles the outside . . . of this case. . . . Took
    three years.” After being given the opportunity to speak with his attorney,
    Cardona decided to waive his presence during the parties’ discussion of jury
    instructions, and his attorney proceeded in his absence.
    Cardona was present for the fourth day of trial and interjected with
    brief comments during the defense’s expert testimony, which led the court to
    admonish him again. After a recess, defense counsel informed the court that
    Cardona wanted to waive his presence again and listen to proceedings from a
    holding cell until closing arguments. The court agreed to instruct the jurors
    that Cardona had exercised his right not to be present, and that they should
    not speculate as to the reasons why. At some point during subsequent
    witness testimony, a pounding noise could be heard in the courtroom coming
    from Cardona’s holding cell.
    After testimony concluded on the fourth day, but before jury
    instructions and closing arguments, Cardona returned to the courtroom and
    the court advised him that if he began disrupting the proceedings, the court
    would “have to take a break and address that.” The rest of the day proceeded
    without incident, and on the fifth and final day of trial, Cardona waived his
    right to have the jury decide the prior conviction allegations.
    When the jury reached a verdict two days later, Cardona was initially
    unwilling to come out of his cell for the reading of the verdict. After
    16
    consulting with his counsel, Cardona agreed to appear in court. However,
    after the verdict was read and while the court was providing final
    instructions to the jury, Cardona interrupted the proceedings and attempted
    to get up from his chair. Cardona was not compliant with deputies’
    commands, so the jury was ordered to leave the courtroom briefly while the
    deputies removed him.
    B. Governing Law
    “The constitutional guarantee of due process forbids a court from trying
    or convicting a criminal defendant who is mentally incompetent to stand
    trial. [Citations.] Section 1367 of the Penal Code, incorporating the
    applicable constitutional standard, specifies that a person is incompetent to
    stand trial ‘if, as a result of mental disorder or developmental disability, the
    defendant is unable to understand the nature of the criminal proceedings or
    to assist counsel in the conduct of a defense in a rational manner.’ ”
    (People v. Rodas (2018) 
    6 Cal.5th 219
    , 230 (Rodas); People v. Buenrostro
    (2018) 
    6 Cal.5th 367
    , 386 [“As a matter of due process, ‘[a] defendant may not
    be put to trial unless he “ ‘has sufficient present ability to consult with his
    lawyer with a reasonable degree of rational understanding . . . [and] a
    rational as well as factual understanding of the proceedings against
    him.’ ” ’ ”].)
    Section 1368 provides for the suspension of criminal proceedings to
    conduct a competency hearing if a doubt arises as to the defendant’s mental
    competence to stand trial. (See People v. Lawley (2002) 
    27 Cal.4th 102
    , 136
    (Lawley).) Our Supreme Court “has construed that provision, in conformity
    with the requirements of federal constitutional law, as meaning that an
    accused has the right ‘to a hearing on present sanity if he comes forward with
    substantial evidence that he is incapable, because of mental illness, of
    17
    understanding the nature of the proceedings against him or of assisting in his
    defense.’ ” (Rodas, supra, 6 Cal.5th at p. 231.) “When a doubt exists as to the
    defendant’s mental competence, the court must appoint an expert or experts
    to examine the defendant. The issue is then tried to the court or a jury under
    the procedures set out in Penal Code section 1369.” (Ibid.)
    However, a defendant is presumed competent unless proven otherwise
    by a preponderance of the evidence (§ 1369, subd. (f)), and “a defendant must
    exhibit more than bizarre, paranoid behavior, strange words, or a preexisting
    psychiatric condition that has little bearing on the question of whether the
    defendant can assist his [or her] defense counsel” (People v. Ramos (2004) 
    34 Cal.4th 494
    , 508 (Ramos)) before the trial court is obligated to order a
    competency hearing. Evidence “ ‘that does no more than form the basis for
    speculation regarding possible current incompetence is not sufficient.’
    [Citations.]” (People v. Ramirez (2006) 
    39 Cal.4th 398
    , 431 (Ramirez).)
    Moreover, “ ‘[w]hen a competency hearing has already been held and
    defendant has been found competent to stand trial, . . . a trial court need not
    suspend proceedings to conduct a second competency hearing unless it “is
    presented with a substantial change of circumstances or with new evidence”
    casting a serious doubt on the validity of that finding.’ ” (People v. Kelly
    (1992) 
    1 Cal.4th 495
    , 542.) A trial court may rely on its own observations in
    determining whether the defendant’s mental state has significantly changed
    during the course of trial to necessitate a new competency hearing. (People v.
    Jones (1991) 
    53 Cal.3d 1115
    , 1153.)
    “We review a trial court’s determination concerning whether a new
    competency hearing must be held for substantial evidence.” (People v.
    Ng (2022) 
    13 Cal.5th 448
    , 531.)
    18
    C. Analysis
    Cardona primarily asserts that his actions and comments during the
    pretrial motion hearing and throughout trial showed that between the
    competency findings in March and July 2019, and his trial in January 2020,
    Cardona was “showing mental decompensation” because he “was not taking
    his medication.” According to Cordona, this constituted “evidence casting
    doubt on the initial competency findings.”
    Importantly, however, the evidence shows Cardona was not taking
    medication at the time of his prior competency evaluations. During his
    interview for the March 2019 competency report, Cardona said that although
    he had received treatment at a hospital and taken medications in the past, he
    was not taking any mental health medications at that time. In July 2019,
    Cardona again reported that he was not under the care of a jail psychiatrist
    and was not taking any psychiatric medications because they “weigh him
    down.” Given that Cardona was not taking medication at either time when
    two different psychiatrists deemed him competent, the fact that he was not
    taking medication shortly before or during trial was not a change of
    circumstances that would warrant suspending the proceedings yet again.
    Nor did Cardona’s behavior in court constitute substantial evidence of
    materially changed circumstances casting doubt on the validity of the prior
    findings of competence. Although Cardona frequently stood during trial
    despite the court’s orders to remain seated, the first evaluating psychiatrist
    observed that Cardona “did not want to sit down for the interview and
    wanted to stand for the interview.” That same psychiatrist also noted that
    Cardona sometimes had to be asked the same questions repeatedly, and that
    Cardona would “ramble at times[.]” The second psychiatrist similarly
    reported that Cardona “fluctuated in his cooperation” with answering
    19
    questions, “showed difficulty with remaining focused[,]” and “frequently
    changed the subject of questions asked,” going on “short tangents questioning
    his own willingness to cooperate with the evaluation, before eventually
    deciding to continue.”
    These observations are largely consistent with Cardona’s comments
    and outbursts during trial, which lends further support to the trial court’s
    decision that another competency hearing was not necessary. (See Lawley,
    
    supra,
     27 Cal.4th at pp. 136–138 [each instance cited by defendant as an
    example of his incompetence “appears . . . to manifest the same arguably
    delusional beliefs” reported by the two evaluating psychologists who found
    defendant competent].) “[T]he duty to suspend is not triggered by
    information that substantially duplicates evidence already considered at an
    earlier, formal inquiry into the defendant’s competence; when faced with
    evidence of relatively minor changes in the defendant’s mental state, the
    court may rely on a prior competency finding rather than convening a new
    hearing to cover largely the same ground.” (Rodas, supra, 6 Cal.5th at
    pp. 234–235.) Here, because Cardona’s behavior in court was similar to his
    behavior during prior competency evaluations, the record does not show any
    substantial change of circumstances or new evidence casting doubt on the
    prior findings of competency. (Lawley, at pp. 137–138.)
    Furthermore, occasional bizarre behavior and “strange words,” by
    themselves, shed little light on the question of whether the defendant can
    assist in his own defense. (See Ramos, 
    supra,
     34 Cal.4th at p. 508.) Unlike
    in People v. Easter (2019) 
    34 Cal.App.5th 226
    , which Cardona cites to in his
    briefs, there was no indication here that Cardona’s communications with his
    attorney were compromised to the extent that they “consisted of jumbled
    words and fanciful responses,” making it impossible for him to “hold a logical
    20
    conversation, consult with [his attorney] with a rational degree of
    understanding, or assist in his own defense or testify at trial.” (See id. at
    p. 243.) Although his attorney requested that Cardona be evaluated to
    address “medication issues,” his counsel never reported having significant
    trouble communicating or consulting with Cardona during trial.
    Rather, the trial record shows that on multiple occasions, Cardona
    appeared able and willing to consult with his attorney during instances when
    the court confronted him about his disruptive behavior, when he decided to
    waive his presence, and when he waived his right to a jury trial on the prior
    conviction allegations. More than once, Cardona even apologized to the court
    for disrupting proceedings and said he would do his “best to refrain from
    that.”
    The two evaluating psychiatrists for the pretrial competency
    proceedings also concluded that despite Cardona’s tendency to ramble, go on
    tangents, and change the subject of questions, he still had “the ability to
    understand the nature of the proceedings against him[,]” could “cooperate
    with his attorney in a rational manner in his own defense[,]” and “appear[ed]
    capable of assisting his attorney in a rational defense[.]” The psychiatrists
    observed that Cardona had no active symptoms of schizoaffective disorder, no
    psychotic symptoms, and “no diagnosable severe mental illness.”
    We must accord great deference to a trial court’s decision not to order a
    competency hearing, because the trial court is uniquely situated to observe
    the defendant’s conduct and demeanor and relative ability to understand the
    nature of the proceedings and rationally conduct a defense. (People v.
    Danielson (1992) 
    3 Cal.4th 691
    , 726–727.) And while Cardona’s behavior
    provided some basis for speculating about a possible mental disorder or
    developmental disability, speculation is an insufficient basis for requiring the
    21
    suspension of proceedings for a third time. (Ramirez, 
    supra,
     39 Cal.4th at
    p. 431.) We therefore conclude that the trial judge—who was aware Cardona
    had been found competent on two prior occasions within the year before trial,
    and who was able to observe his conduct at trial as a whole and in context—
    did not err by declining to sua sponte order a third competency hearing.
    II
    We turn next to Cardona’s arguments that the trial court prejudicially
    erred in failing to instruct the jury on (1) voluntary manslaughter based on
    imperfect self-defense, and (2) mental impairment as a defense to specific
    intent. We conclude that the trial court did not err in declining to give these
    instructions because substantial evidence did not support instructing the jury
    on either of them. We further conclude that even if the court did err in
    declining to give either of these instructions, any error was harmless.
    A. Governing Law
    Voluntary manslaughter based on imperfect self-defense is a lesser
    included offense of murder. The trial court has a duty to instruct on this
    theory “whenever the evidence is such that a jury could reasonably conclude
    that the defendant killed the victim in the unreasonable but good faith belief
    in having to act in self-defense.” (People v. Barton (1995) 
    12 Cal.4th 186
    , 201
    (Barton).)
    A trial court has no sua sponte duty to instruct on mental impairment
    as a defense to a specific mental state. (People v. Saille (1991) 
    54 Cal.3d 1103
    , 1119.) If requested by the defense, however, the trial court must give a
    pinpoint instruction on mental impairment if there is evidence supportive of
    the theory. (Ibid.)
    A trial judge “has the authority to refuse requested instructions on a
    defense theory for which there is no supporting evidence.” (People v.
    22
    Ponce (1996) 
    44 Cal.App.4th 1380
    , 1386.) Even requested instructions need
    not be given to the jury “absent substantial evidence to support them.”
    (People v. Stitely (2005) 
    35 Cal.4th 514
    , 551); accord, People v.
    Nguyen (2015) 
    61 Cal.4th 1015
    , 1049 (Nguyen).) On review, we determine
    independently whether substantial evidence to support a requested
    instruction existed. (People v. Shelmire (2005) 
    130 Cal.App.4th 1044
    , 1055;
    see People v. Mentch (2008) 
    45 Cal.4th 274
    , 288 [“On appeal, we likewise ask
    only whether the requested instruction was supported by substantial
    evidence—evidence that, if believed by a rational jury, would have raised a
    reasonable doubt . . . .”].)
    B. Jury Instruction on Imperfect Self-Defense
    At trial, the defense requested that the court instruct the jury on
    voluntary manslaughter based on imperfect self-defense (CALCRIM No. 571).
    The People objected, arguing that under the bracketed portions of the
    instruction, imperfect self-defense “does not apply when the defendant,
    through [his] own wrongful conduct, has created circumstances that justify
    [his] adversary’s use of force.” (CALCRIM No. 571.) The People also argued
    that Cardona never expressed fear of N.J. or concern for his own safety, aside
    from telling detectives that he wanted to prevent N.J. from taking advantage
    of him in the fight. The court initially sided with the defense, but after
    further consideration, the court agreed with the People that the instruction
    was unwarranted because the evidence was not sufficient to show that
    Cardona believed he was in danger of imminent harm or great bodily injury.
    There are two types of self-defense under California law: “perfect” self-
    defense and “imperfect” self-defense. (People v. Randle (2005) 
    35 Cal.4th 987
    ,
    994.) “For perfect self-defense, one must actually and reasonably believe in
    the necessity of defending oneself from imminent danger of death or great
    23
    bodily injury.” (Ibid.) Imperfect self-defense requires evidence showing the
    “ ‘defendant killed another person because the defendant actually, but
    unreasonably, believed he was in imminent danger of death or great bodily
    injury . . . .’ ” (Nguyen, 
    supra,
     61 Cal.4th at p. 1048, italics added.) In
    contrast to perfect self-defense, imperfect self-defense is not a true
    affirmative defense; it is shorthand for a theory of voluntary manslaughter.
    (Barton, 
    supra,
     12 Cal.4th at pp. 199–201.)
    For imperfect self-defense to apply, “the fear must be of imminent
    harm.” (People v. Humphrey (1996) 
    13 Cal.4th 1073
    , 1082.) A fear of future
    harm will not suffice no matter how great the fear and likelihood of harm.
    (People v. Landry (2016) 
    2 Cal.5th 52
    , 97–98; People v. Manriquez (2005) 
    37 Cal.4th 547
    , 581–582.) Furthermore, imperfect self-defense cannot be used
    by a defendant whose wrongful conduct creates circumstances under which
    the victim’s actions are legally justified. (In re Christian S. (1994) 
    7 Cal.4th 768
    , 773, fn. 1 (Christian S.).)
    Here, we conclude that the imperfect self-defense instruction was
    unwarranted because the evidence did not show Cardona actually believed,
    reasonably or unreasonably, that he was in imminent danger of death or
    great bodily injury. In his interrogation, Cardona told detectives that he
    stayed on top of N.J. with his knee against his back because “. . . I didn’t
    know if [N.J.] was going to grab me and like try to take advantage of me to
    where I was in a position to defend myself.” (Italics added.) When asked
    whether he could have walked away from the altercation after N.J. was face
    down and Cardona had the position of advantage, he agreed that he could
    have chosen to get off N.J.—but he continued to hit N.J. because he was
    “waiting for an answer” regarding his sunglasses. Cardona also explained
    that when he was on top of N.J. while N.J. was face down on the ground, he
    24
    “just wanted to get in that position to where he wasn’t trying to like . . . hurt
    [him].” This statement establishes that Cardona kept his knee on N.J.’s back
    only to maintain the upper hand while he was attacking N.J. Cardona’s
    statements do not establish that his aggressive acts were in response to any
    actual belief that he needed to defend himself from danger of death or great
    bodily injury.
    Furthermore, there is no evidence that Cardona had reason to fear N.J.
    based on their prior interactions. According to Cardona, he had a good
    relationship with N.J., and they had never fought before or had any issues in
    the past. Other family members testified that they had never seen the two
    argue and they were not aware of any problems between them. Cardona also
    made no mention of N.J. threatening him or using a weapon against him
    either before or during the incident.
    Even if Cardona did actually believe N.J. was a threat or posed some
    kind of danger, there is no evidence he believed that danger was imminent.
    Imperfect self-defense only applies when the defendant fears immediate
    harm that “ ‘must be instantly dealt with.’ [Citation.]” (People v. Beck and
    Cruz (2019) 
    8 Cal. 5th 548
    , 648, internal quotation marks omitted.) Here, the
    only harm Cardona mentioned was the possibility that N.J. might fight back
    against him, but there is no indication he believed such potential danger was
    imminent. Cardona had his knee on N.J.’s back while N.J. was lying prone
    on the ground, and Vanessa testified that for the entire time she was
    watching them, N.J. never changed positions, never hit or kicked Cardona,
    and never fought back.
    The fact that Cardona was the instigator of the fight also supports the
    trial court’s finding that there was no basis for an imperfect self-defense
    instruction. (See Christian S., supra, 7 Cal.4th at p. 773, fn. 1.) As the
    25
    People noted at trial, imperfect self-defense does not apply when the
    defendant, through his own wrongful conduct, has created circumstances that
    justify his adversary’s use of force. (Ibid.) Here, Cardona admitted after his
    arrest that the brawl started when he punched N.J. in the mouth. Cardona
    said that N.J. then pushed him back and they “were struggling in the house,”
    but once they got outside, there was a point at which N.J. no longer fought
    back. The record shows that Cardona instigated and continued the physical
    confrontation that led to N.J.’s death, which supports the trial court’s
    decision not to give the imperfect self-defense instruction.
    Cardona argues that because the court gave the instruction on perfect
    self-defense, there must have been a basis for the jury to find he acted in
    imperfect self-defense. But “just because the court permitted instructions on
    perfect self-defense does not mean that substantial evidence supported the
    giving of an imperfect self-defense instruction.” (People v. Rodriguez (1997)
    
    53 Cal.App.4th 1250
    , 1270.) Given the evidence in this case, we conclude
    that “it would not have been error for the trial court to have denied perfect
    self-defense instructions with regard to [the victim] because no substantial
    evidence supported such a defense.” (Ibid.)
    Even assuming the trial court erred by not giving an imperfect self-
    defense instruction, the record does not show that the error was prejudicial.
    The failure to instruct on imperfect self-defense constitutes reversible error
    only if the defendant establishes that it is reasonably probable he would have
    obtained a more favorable outcome had the error not occurred. (People v.
    Gonzalez (2018) 
    5 Cal.5th 186
    , 191, 197–199, 200, fn. 4 (Gonzalez) [“. . . we
    have since clarified that Watson applies to the failure to instruct on lesser
    included offenses.”]; see People v. Watson (1956) 
    46 Cal.2d 818
    , 836
    (Watson).) In applying this harmless error analysis, a court must be mindful
    26
    that the failure to provide the jury with the option of convicting on voluntary
    manslaughter “creates a specific kind of risk—that the jury, faced with an all-
    or-nothing choice between first degree murder or acquittal” will convict the
    defendant of murder even though the prosecution failed to satisfy its burden
    to prove the crime. (Gonzalez, at pp. 191, 200.)
    The question, however, “is not what a jury could have done, but what a
    jury would likely have done if properly instructed.” (People v. Reeves (2001)
    
    91 Cal.App.4th 14
    , 53; see People v. Breverman (1998) 
    19 Cal.4th 142
    , 177,
    178.).) “ ‘In making that evaluation, an appellate court may consider, among
    other things, whether the evidence supporting the existing judgment is
    so relatively strong, and the evidence supporting a different outcome is
    so comparatively weak, that there is no reasonable probability the error of
    which the defendant complains affected the result.’ [Citation.]” (People v.
    Russell (2006) 
    144 Cal.App.4th 1415
    , 1432.) We also consider the
    instructions as a whole, the jury’s findings, and the closing arguments of
    counsel. (People v. Cain (1995) 
    10 Cal.4th 1
    , 35–36; People v. Eid (2010) 
    187 Cal.App.4th 859
    , 883.)
    Here, for the reasons we have discussed, it would have been a stretch
    for any reasonable juror to conclude that Cardona genuinely believed he was
    in imminent danger of death or great bodily injury when he had his victim
    restrained face down on the ground and was beating him mercilessly simply
    for not answering his questions. The fact that Cardona was the instigator of
    the fight also made it unlikely the jury would find he acted with a belief in
    the need for self-defense. Cardona points to the fact that the jury asked for a
    readback of the two law enforcement officers’ testimony and for clarification
    of the instruction on murder to argue that it is reasonably probable he would
    have obtained a more favorable outcome if the jury was instructed on
    27
    imperfect self-defense. However, the readback covered a wide range of topics,
    including all of the responding officer’s interactions with Cardona that
    morning and Cardona’s post-arrest statements, and there is no indication the
    jury’s request was specifically related to the issue of self-defense.
    Furthermore, the jury’s question about CALCRIM No. 520 focused on the
    meaning of “dangerous to human life” for purposes of determining whether he
    acted with implied malice, not whether he acted in self-defense.
    Finally, the jury in this case was not faced with an “all-or-nothing
    choice between first degree murder or acquittal”—rather, the court instructed
    the jury on second-degree murder, perfect self-defense, voluntary
    manslaughter based on heat of passion, and involuntary manslaughter. (See
    Gonzalez, 
    supra,
     5 Cal.5th at pp. 191, 200.) On the topic of self-defense,
    Cardona’s counsel argued in closing that N.J. actually instigated the fight by
    “start[ing] an argument over a stove[,]” perhaps because he was under the
    influence of methamphetamine. He also argued that N.J. may have
    threatened Cardona with a frying pan or with a broken chair leg. Later in
    his closing, Cardona’s counsel repeated these points to argue for finding that
    Cardona was provoked for heat-of-passion purposes. But in finding Cardona
    guilty of second-degree murder, the jury appears to have rejected those
    attempts to argue that Cardona was not the instigator, making it even more
    improbable that the jury would have found Cardona acted in imperfect self-
    defense. For all these reasons, we conclude that any error from declining to
    instruct the jury on imperfect self-defense was harmless under Watson.
    C. Jury Instruction on Mental Impairment
    Cardona’s counsel also requested that the court instruct the jury on
    mental impairment to negate the specific intent element of the charged
    28
    offense (CALCRIM No. 3428).4 At trial, the People argued that the
    instruction was inappropriate because the evidence did not establish that
    Cardona suffers from a mental disease, defect, or disorder. In response, the
    defense pointed to evidence indicating that Cardona was acting oddly and not
    taking “his meds” at the time of the incident.
    The court stated that the evidence did not establish whether or when
    Cardona was off medication, and even if it had, it was unclear what that
    medication was for. The court ultimately denied the defense’s request for the
    instruction on the basis that the evidence presented was insufficient to show
    that Cardona suffered from a mental disease or disorder.
    CALCRIM No. 3428 “is a pinpoint instruction that must be given only if
    requested by the defendant, and only if substantial evidence supports the
    defense theory that defendant’s mental disease or disorder affected the
    formation of the relevant intent or mental state. [Citation.] Also, expert
    medical opinion testimony is necessary to establish that a defendant suffered
    from a mental disease, mental defect, or mental disorder within the meaning
    of CALCRIM No. 3428, because jurors cannot make such a determination
    from common experience.” (People v. Larsen (2012) 
    205 Cal.App.4th 810
    , 824
    (Larsen); see also People v. Moore (2002) 
    96 Cal.App.4th 1105
    , 1117 [“Expert
    medical testimony is necessary to establish a defendant suffered from a
    mental disease, mental defect, or mental disorder because jurors cannot
    make such a determination from common experience”].)
    4     CALCRIM No. 3428 instructs, in relevant part, as follows: “You have
    heard evidence that the defendant may have suffered from a mental
    (disease[,]/ [or] defect[,]/ [or] disorder). You may consider this evidence only
    for the limited purpose of deciding whether, at the time of the charged crime,
    the defendant acted [or failed to act] with the intent or mental state required
    for that crime.”
    29
    Here, Cardona introduced no expert testimony regarding any mental
    defect or disorder, and he failed to introduce any other evidence that he
    suffered from a specific mental disorder or impairment at the time of the
    offense. As the trial court noted, the record does not establish what kind of
    medication, if any, he was taking when the fight occurred. Cardona received
    treatment for a cut above his eye the day before the incident, but the record
    indicates he was prescribed pain medication, not medication to treat a mental
    disease or disorder. Although Cardona reported during his interrogation that
    he had previously been diagnosed with schizoaffective disorder, that evidence
    was not presented to the jury and there was no evidence confirming that
    diagnosis, let alone showing whether Cardona was suffering from symptoms
    of schizoaffective disorder at the time of the crime. Given this record, we
    conclude that the trial court did not err in finding that no substantial
    evidence supported instructing the jury on mental impairment.
    Even assuming error, the record does not show that declining to give
    the mental impairment instruction was prejudicial. Prejudice resulting from
    the failure to give a pinpoint instruction is assessed under the state
    constitutional standard requiring reversal only if it is reasonably probable
    the jury would have reached a different result if the omitted instruction had
    been given. (Larsen, supra, 205 Cal.App.4th at p. 829; see Watson, supra, 46
    Cal.2d at p. 836.) Here, even if the jury received the instruction on mental
    impairment, the jury would have had no evidence to rely on in considering
    whether a mental disease or defect prevented Cardona from acting with the
    intent required for murder. The defense failed to present sufficient evidence
    of a mental disease or defect, and also failed to connect any of Cardona’s
    supposed symptoms with the evidence of his intent. (See Larsen, at p. 833
    [failure to instruct on mental impairment was harmless where “the
    30
    connection between the symptoms of defendant’s Asperger’s syndrome and
    the evidence of intent to commit the charged conspiracy was not at all
    persuasive, and the evidence of guilt was compelling.”].) In contrast, as
    discussed below, the evidence that Cardona acted with the implied malice
    required for second-degree murder was substantial. Accordingly, it is not
    reasonably probable that the jury in this case would have reached a different
    result if CALCRIM No. 3428 had been given.
    III
    Cardona next argues that the trial court erred in finding that he
    waived his Miranda rights during his interrogation and admitting his post-
    arrest statements at trial. We conclude that the trial court did not err
    because even though there was no express waiver, Cardona impliedly waived
    his Miranda rights, and any potential error was harmless beyond a
    reasonable doubt.
    A. Additional Relevant Facts
    At the beginning of his custodial interrogation, one of the two
    interrogating detectives informed Cardona of his Miranda rights and
    Cardona confirmed he understood them. The detective did not ask Cardona a
    follow-up question to confirm his waiver of those rights before proceeding
    with questioning. According to the detective, however, Cardona was willing
    to speak with him and answered his questions fully. Before the
    interrogation, Cardona’s sister told the detective that Cardona had a mental
    illness and was taking psychiatric medication, but the detective did not know
    the severity of Cardona’s mental illness and it appeared to him that Cardona
    understood what was happening during the questioning.
    At trial, the defense sought to exclude Cardona’s statements on
    Miranda grounds. The court reviewed the transcript, video, and audio
    31
    recordings from Cardona’s post-arrest interview. The court also heard
    testimony from one of the interrogating detectives. After hearing arguments
    from the parties, the court found that the detective properly advised Cardona
    of his Miranda rights, and that Cardona impliedly waived those rights by
    willingly subjecting himself to questioning. The court determined that the
    detectives did not use coercive physical or psychological tactics, and that even
    though Cardona has mental impairments, they were not so severe as to make
    his statements unreliable or overcome his ability to voluntarily and implicitly
    waive his Miranda rights. Accordingly, the court denied the defense’s
    request to exclude Cardona’s interrogation statements.
    B. Governing Law
    “In general, if a custodial suspect, having heard and understood a full
    explanation of his . . . Miranda rights, then makes an uncompelled and
    uncoerced decision to talk, he . . . has thereby knowingly, voluntarily, and
    intelligently waived them. [Citation.] Law enforcement officers are not
    required to obtain an express waiver of a suspect’s Miranda rights prior to a
    custodial interview. [Citation.] Rather, a valid waiver of Miranda rights
    may, as here, be inferred from the defendant’s words and actions. [Citation.]”
    (People v. Cunningham (2015) 
    61 Cal.4th 609
    , 642 (Cunningham).)
    Whether a statement is voluntary depends on “whether the statement
    is ‘ “the product of an essentially free and unconstrained choice” ’ or whether
    the defendant’s ‘ “will has been overborne and his capacity for self-
    determination critically impaired” ’ by coercion. [Citation.] No single factor
    is dispositive; ‘rather courts consider the totality of [the] circumstances.’
    [Citations.]” (Cunningham, supra, 61 Cal.4th at p. 642.) Relevant
    considerations include the level of coercion, the length and location of the
    32
    interrogation, its continuity, and the defendant’s maturity, education, and
    physical and mental health. (Id. at pp. 642–643.)
    “ ‘On review of a trial court’s decision on a Miranda issue, we accept the
    trial court’s determination of disputed facts if supported by substantial
    evidence, but we independently decide whether the challenged statements
    were obtained in violation of Miranda.’ [Citation.]” (People v. Hensley (2014)
    
    59 Cal.4th 788
    , 809.)
    C. Analysis
    We conclude that the totality of the circumstances of Cardona’s
    interrogation support that he waived his Miranda rights knowingly and
    voluntarily. After the detective informed him of his rights, Cardona
    confirmed that he understood them and continued to talk to the detectives.
    Neither the length nor physical circumstances of the interrogation appeared
    to be coercive; the questioning lasted less than 1.5 hours; he was not deceived
    or induced by improper promises; and the tone of the interview, as evidenced
    in the transcript and video, was calm, respectful, non-accusatory, and non-
    threatening. (See Cunningham, 
    supra,
     61 Cal.4th at p. 644 [statements
    voluntary where interview “was spread over a four-hour period” and “the tone
    of the questioning as evidenced in the transcript [was not] particularly harsh
    or accusatory”]; People v. Whitson (1998) 
    17 Cal.4th 229
    , 249 (Whitson)
    [finding waiver voluntary where defendant’s “willingness to speak with the
    officers [was] readily apparent from his responses” and he was “not worn
    down by improper interrogation tactics, lengthy questioning, or trickery or
    deceit”].) Cardona even confirmed at one point during the interrogation that
    he was not being forced to talk to the detectives, stating that he “just
    want[ed] to be honest, that’s all.”
    33
    Although late in the interrogation Cardona asked if he “need[ed] to hire
    a lawyer[,]” a suspect who wishes to invoke the right to counsel “must do so
    ‘unambiguously[,]’ ” and merely positing that “ ‘[m]aybe I should talk to a
    lawyer’ ” is insufficient. (People v. Tom (2014) 
    59 Cal.4th 1210
    , 1225; see
    Davis v. U.S. (1994) 
    512 U.S. 452
    , 462 (Davis).) Under Davis, it is not enough
    that a suspect makes a reference to an attorney “that a reasonable officer in
    light of the circumstances would have understood” to mean “only that the
    suspect might be invoking the right to counsel.” (Davis, at p. 459; see also
    People v. Nelson (2012) 
    53 Cal.4th 367
    , 376 (Nelson).) Given the ambiguous
    nature of Cardona’s question, it was reasonable for the detectives to believe it
    was not a clear invocation of his right to counsel.
    Additionally, “[e]ven though officers may ask questions to clarify
    whether the right to counsel is being invoked, they are not obligated to do so.”
    (Nelson, 
    supra,
     53 Cal.4th at p. 377.) Here, after Cardona asked if he needed
    to hire a lawyer, the detective responded, “That’s not for us to say. We are
    just trying to see if you understand why we’re talking to you, why it is that
    you’re here.” The detective then followed up by asking whether Cardona
    “ha[d] any problem with us talking to you about this incident?” Cardona
    replied, “No.” Thus, even though the detectives were not obligated to seek
    clarification about Cardona’s willingness to continue speaking with them,
    they did so here, and there is no evidence that Cardona’s statements were not
    voluntarily given.
    Although Cardona sometimes asked for questions to be repeated or
    rephrased, he was generally able to answer coherently and with apparent
    understanding. One of the interrogating detectives testified that Cardona
    was alert, willing to speak with him, and answered his questions fully. The
    interrogation transcript and video support the detective’s testimony, and
    34
    there is no evidence that Cardona’s judgment was clouded or otherwise
    impaired during the interview by pain, medications, or medical procedures.
    (See Whitson, 
    supra,
     17 Cal.4th at p. 249.)
    Even if some of Cardona’s behavior “was irrational or bizarre, there is
    no evidence his ‘abilities to reason or comprehend or resist were in fact so
    disabled that he was incapable of free or rational choice. [Citations.]’ ”
    (Cunningham, 
    supra,
     61 Cal.4th at p. 645; see, e.g., People v. Mayfield (1993)
    
    5 Cal.4th 142
    , 204 [defendant, who may have been under the influence of
    drugs or his diabetic condition at the time of his lengthy interview, did not
    appear mentally impaired because he sounded lucid, spoke clearly albeit
    slowly, and at times “engaged in animated” conversation with detectives].)
    Although Cardona’s sister mentioned to the detectives that he suffered from
    mental illness, it appeared that he had little difficulty understanding what
    was happening during the interview. Based on the totality of the evidence,
    including our own review of the videotaped interrogation, Cardona
    understood the detectives and responded appropriately to their questions.
    There is also evidence in the record indicating that Cardona had prior
    experience with law enforcement. Cardona acknowledged at the end of his
    interrogation that he had previous arrests for fighting with police officers.
    He also mentioned being incarcerated, and the record shows he was convicted
    of attempted carjacking in 2007. While the record does not indicate whether
    Cardona was advised of his Miranda rights on other occasions, a defendant’s
    prior encounters with law enforcement can be considered in determining
    whether a waiver was knowing and voluntary. (See, e.g., People v. Lessie
    (2010) 
    47 Cal.4th 1152
    , 1169 [“While no evidence was offered that defendant
    had, or had not, previously been advised of his rights under Miranda, . . . he
    was no stranger to the justice system.”].) Given the totality of the
    35
    circumstances here, we conclude that Cardona impliedly waived his Miranda
    rights, and his statements were properly admitted.
    Even if any error occurred, however, it was harmless beyond a
    reasonable doubt. Erroneous admission of statements made in violation of
    Miranda is subject to harmless error analysis under Chapman v. California
    (1967) 
    386 U.S. 18
     (Chapman). Under Chapman, a constitutional error is
    harmless when it appears “beyond a reasonable doubt that the error
    complained of did not contribute to the verdict obtained.” (Id. at p. 24.) Here,
    the evidence presented at trial included testimony from multiple
    eyewitnesses describing, in great detail, how Cardona punched N.J.
    repeatedly while N.J. was in a vulnerable prone position. An audio recording
    corroborated eyewitness testimony and even captured N.J.’s screams for help.
    Two eyewitnesses testified that at one point, Cardona reached under N.J.’s
    neck and forcefully pulled it backwards before releasing it and letting N.J.
    fall to the ground hard, after which N.J. went limp.
    The responding officer further testified about how Cardona continued
    to try to kick N.J., even while Cardona was handcuffed and N.J. was lying
    motionless. Blood tested from the scene belonged to N.J. and not Cardona,
    which is circumstantial evidence that Cardona was the aggressor even
    without his own statements confirming as much. Finally, the medical
    examiner opined that N.J.’s injuries were consistent with witnesses’
    descriptions of what happened, and she concluded that “head and neck
    trauma” were contributing factors in N.J.’s homicide. On this record, we
    agree with the People that any error in admitting Cardona’s statements was
    harmless beyond a reasonable doubt.
    As for Cardona asking whether he needed a lawyer, even if Cardona’s
    question could be viewed as an unambiguous invocation of his right to an
    36
    attorney, his question came after the portions of his interview that were
    admitted into evidence and played for the jury. Because only statements
    made after unambiguous invocation are inadmissible, any potential error in
    finding that Cardona did not clearly invoke his right to counsel would be
    harmless in this case. (See, e.g., People v. Storm (2002) 
    28 Cal.4th 1007
    , 1021
    [“ ‘A suspect, having invoked these rights, is not subject to further
    interrogation by the police until counsel has been made available to him . . . .
    [Citations.]’ ” (Italics added.)].) Accordingly, we conclude that the trial court
    did not prejudicially err in admitting portions of his post-arrest statements
    into evidence.
    IV
    Lastly, Cardona contends there was insufficient evidence to support the
    jury’s finding of guilt for second-degree murder. Specifically, he argues there
    was no substantial evidence that he harbored implied malice, or that his
    actions proximately caused N.J.’s death. We disagree and conclude that
    there was substantial evidence to support the jury’s verdict.
    A. Governing Law
    In response to an appellant’s challenge to the sufficiency of the
    evidence supporting his conviction, we must determine “ ‘whether, after
    viewing the evidence in the light most favorable to the prosecution, any
    rational trier of fact could have found the essential elements of the crime
    beyond a reasonable doubt.’ ” (Nguyen, supra, 61 Cal.4th at p. 1055.) “The
    record must disclose substantial evidence to support the verdict—i.e.,
    evidence that is reasonable, credible, and of solid value—such that a
    reasonable trier of fact could find the defendant guilty beyond a reasonable
    doubt.” (People v. Zamudio (2008) 
    43 Cal.4th 327
    , 357.) “[W]e review the
    evidence in the light most favorable to the prosecution and presume in
    37
    support of the judgment the existence of every fact the jury could reasonably
    have deduced from the evidence.” (Ibid.) “ ‘Conflicts and even testimony
    [that] is subject to justifiable suspicion do not justify the reversal of a
    judgment, for it is the exclusive province of the trial judge or jury to
    determine the credibility of a witness and the truth or falsity of the facts
    upon which a determination depends. [Citation.] We resolve neither
    credibility issues nor evidentiary conflicts; we look for substantial
    evidence.’ ” (Ibid.) “A reversal for insufficient evidence ‘is unwarranted
    unless it appears “that upon no hypothesis whatever is there sufficient
    substantial evidence to support” ’ the jury’s verdict.” (Ibid.)
    “[S]econd degree murder . . . is ‘the unlawful killing of a human being
    with malice aforethought but without the additional elements, such as
    willfulness, premeditation, and deliberation, that would support a conviction
    of first degree murder.’ [Citation.] . . . ‘Malice is implied when the killing is
    proximately caused by “ ‘an act, the natural consequences of which are
    dangerous to life, which act was deliberately performed by a person who
    knows that his conduct endangers the life of another and who acts with
    conscious disregard for life.’ ” [Citation.] In short, implied malice requires a
    defendant’s awareness of engaging in conduct that endangers the life of
    another . . . .’ ” (People v. Cravens (2012) 
    53 Cal.4th 500
    , 507.) Implied
    malice may be proven by circumstantial evidence. (People v. Smith (2009)
    
    178 Cal.App.4th 475
    , 479 [“Because intent can seldom be proven by direct
    evidence, it typically is inferred from the circumstances.”].)
    Regarding proximate cause, an act causes death if the death is the
    direct, natural, and probable consequence of the act, and the death would not
    have happened without the act. (See People v. Cervantes (2001) 
    26 Cal.4th 860
    , 866–874; People v. Roberts (1992) 
    2 Cal.4th 271
    , 315–321.) There may
    38
    be more than one cause of death, and an act causes death only if it is a
    substantial factor in causing the death. (People v. Sanchez (2001) 
    26 Cal.4th 834
    , 845–849.) A substantial factor is more than a trivial or remote factor;
    however, it does not need to be the only factor that causes the death. (See id.
    at p. 845.) “California courts have long held ‘that there may be multiple
    proximate causes of a homicide[.]’ ” (People v. Garcia (2022) 
    82 Cal.App.5th 956
    , 963 (Garcia); see also People v. Jennings (2010) 
    50 Cal.4th 616
    , 643 [a
    defendant may be criminally liable for a result directly caused by his or her
    act, even though there is another contributing cause].)
    B. Analysis
    Here, there was substantial evidence to establish that Cardona
    violently attacked N.J., knowing it endangered his life, and that Cardona
    acted with a conscious disregard for N.J.’s life. As noted, according to
    Vanessa’s testimony, N.J. yelled for Cardona to stop hitting him and said,
    “You’re going to kill me.” Although Cardona denied hearing N.J. say that, he
    acknowledged in his interrogation that he heard Vanessa tell him to stop
    hitting N.J. because he was “killing him.” The evidence shows that Cardona
    punched N.J. “nonstop” around his head for about ten minutes while N.J. was
    lying face down with his shirt pulled over his face. Cardona also admitted
    post-arrest that he could have walked away from the altercation but
    continued to hit N.J. with his knee pressed against his back because he was
    “waiting for an answer” regarding his sunglasses. Even after Cardona was
    handcuffed, he continued to attack N.J., who was lying motionless on the
    ground as the responding officer attempted to render him aid. Cardona’s
    interference even forced the officer to stop administering CPR to N.J. so he
    could restrain Cardona further, despite already deploying his taser several
    39
    times. Viewed in the light most favorable to the verdict, the totality of the
    evidence is sufficient to support that Cardona acted with implied malice.
    We also conclude there was sufficient evidence to show that Cardona’s
    actions were a substantial factor in causing N.J.’s death. Cardona points out
    that none of N.J.’s physical injuries was independently fatal, but there may
    be multiple contributing causes of a homicide. (See Garcia, supra, 82
    Cal.App.5th at p. 963.) Similarly, although methamphetamine was found to
    be a contributing factor in N.J.’s death, the medical examiner testified that
    there was no way to single out any single factor as the cause of death. She
    further testified that while the level of methamphetamine in N.J.’s blood
    could have caused an overdose or increased his risk of fatal cardiac arrest,
    N.J. also could have survived if not for his other injuries. The defense’s own
    expert witness testified that while N.J. may have survived the attack absent
    his methamphetamine use, a person “being . . . choked [while] their head is
    being . . . hit into the ground . . . is potentially fatal if it goes on long enough.”
    Lastly, testimony from Rafael and the 911 dispatcher showed that N.J.
    did not exhibit any obvious physical symptoms of methamphetamine use in
    the hour leading up to the incident, lending support to the People’s theory
    that the concentration of methamphetamine found in N.J.’s blood was falsely
    elevated due to post-mortem redistribution.
    The record ultimately shows that while drug use may have contributed
    to N.J.’s death, it did not negate evidence that Cardona’s actions were a
    substantial factor in causing N.J.’s death. (See People v. Catlin (2001) 
    26 Cal.4th 81
    , 155 [“ ‘So long as a victim’s predisposing physical condition,
    regardless of its cause, is not the only substantial factor bringing about his
    death, that condition . . . in no way destroys the [defendant’s] criminal
    responsibility for the death.’ ”].)
    40
    In sum, we conclude there was substantial evidence to support
    Cardona’s second-degree murder conviction.
    DISPOSITION
    The judgment is affirmed.
    BUCHANAN, J.
    WE CONCUR:
    IRION, Acting P. J.
    DATO, J.
    41