United States v. Ramos-Gonzalez , 787 F.3d 1 ( 2015 )


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  •           United States Court of Appeals
    For the First Circuit
    Nos. 10-1434
    11-1416
    12-1538
    12-1711
    UNITED STATES OF AMERICA,
    Appellee,
    v.
    SONIA N. FLORES-RIVERA, a/k/a Mimi; SANDRA I. FLORES-RIVERA,
    a/k/a Sandy; CARLOS OMAR BERMÚDEZ-TORRES, a/k/a Omar Moreno-
    Espada; CRUZ ROBERTO RAMOS-GONZÁLEZ, a/k/a La R, a/k/a El Gordo,
    a/k/a El Galán, a/k/a Robert Belleza, a/k/a Crucito,
    Defendants, Appellants.
    APPEALS FROM THE UNITED STATES DISTRICT COURT
    FOR THE DISTRICT OF PUERTO RICO
    [Hon. Juan M. Pérez-Giménez, U.S. District Judge]
    Before
    Torruella, Thompson, and Kayatta,
    Circuit Judges.
    Linda Backiel for appellants Sonia N. Flores-Rivera and Cruz
    Roberto Ramos-González.
    H. Manuel Hernández for appellant Sandra I. Flores-Rivera.
    Rafael F. Castro Lang for appellant Carlos Omar Bermúdez-
    Torres.
    Dina Ávila-Jiménez, Assistant United States Attorney, with
    whom Rosa Emilia Rodríguez-Vélez, United States Attorney, Nelson
    Pérez-Sosa, Assistant United States Attorney, Chief, Appellate
    Division, and Juan Carlos Reyes Ramos, Assistant United States
    Attorney, were on brief, for appellee.
    May 22, 2015
    -2-
    KAYATTA, Circuit Judge. These consolidated appeals arise
    from a multi-count indictment alleging that the four appellants--
    Sonia Flores-Rivera ("Sonia"), Sandra Flores-Rivera ("Sandra"),
    Carlos Omar Bermúdez-Torres ("Omar"), Cruz Roberto Ramos-González
    ("Ramos")--and their forty-three co-defendants1 participated in a
    far-reaching drug trafficking conspiracy throughout various parts
    of   eastern   Puerto   Rico.      Following   their    joint   trial,   the
    appellants were convicted and sentenced to prison terms ranging
    from 151 months to life.      They assign error to many facets of their
    trial,    sentencing,   and     post-trial   proceedings.
    Ramos and Omar contend that the district court erred in
    denying their motions for a new trial based on the prosecution's
    failure to disclose material evidence in violation of Brady v.
    Maryland, 
    373 U.S. 83
    (1963).        We agree that, cumulatively, the
    withheld evidence had a "reasonable probability" of changing the
    result for those two appellants.          See United States v. González-
    González, 
    258 F.3d 16
    , 20 (1st Cir. 2001).             We therefore remand
    their cases to the district court for a new trial.               Sonia and
    Sandra press no Brady claims on appeal.           Finding no reversible
    error arising from the claims that they do bring, we affirm their
    convictions and sentences.
    1
    The other indicted co-defendants pled guilty either before
    or during trial.
    -2-
    I.    Background
    A.   The Charged Conspiracy
    A grand jury indicted the appellants and their co-
    defendants   on    August    2,       2007,    on    charges    of   conspiring    to
    distribute, and aiding and abetting the distribution of, cocaine,
    crack-cocaine, heroin, and marijuana within 1,000 feet of a public
    housing project or a public school, see 21 U.S.C. §§ 841(a)(1),
    846, 860 and 18 U.S.C. § 2 (counts one and three through six), in
    addition to possessing firearms in furtherance of those crimes, see
    18 U.S.C. § 924(c)(1)(A) and (o) (count two).2                       On February 5,
    2008, the grand jury returned a superseding indictment bringing
    additional charges against Ramos and five other defendants for
    bribing and tampering with a government witness (counts seven
    through nine) in violation of 18 U.S.C. § 1512(b)(1) and (k); 
    id. § 201(b)(3);
    and 
    id. § 2
    (hereinafter "the witness tampering
    counts").     Prior   to     trial,      the    district       court   granted    the
    prosecution's     motion    to    dismiss      the    witness    tampering   counts
    without prejudice so that those charges could be tried separately.
    2
    Count ten alleged the defendants' joint and several
    liability for forfeiture of $10 million, as authorized by 21 U.S.C.
    § 853. The parties later agreed at trial that the evidence only
    supported up to $3 million, so the judge instructed the jury that
    the $10 million shown in the verdict form "should be reduced to $3
    million at the most."
    -3-
    B.   The Evidence
    In considering a challenge to the sufficiency of the
    evidence following a trial by jury, we typically recite the
    relevant facts in the light most favorable to the jury's verdict.
    See United States v. Bayes, 
    210 F.3d 64
    , 65—66 (1st Cir. 2000).
    Conversely, our precedent manifests a lack of consensus on how to
    present the record when a challenge is lodged to other issues, such
    as claims of prejudicial error.       See United States v. Burgos-
    Montes, No. 13-2305, slip op. at 2—3 & n.1 (1st Cir. May 13, 2015).
    Given that we cannot simultaneously recite the facts in
    more than one manner, we first provide a more or less neutral
    summary of the key relevant evidence presented at trial.    In our
    subsequent analysis of each issue we adopt a Rashomon-like approach
    to our view of the evidence depending on the precise question posed
    by the applicable principles of substantive law.   For example, if
    a prosecution witness plausibly says "X" and a witness favorable to
    the defense plausibly claims "not X," we may initially recite both
    but, in considering the sufficiency challenge, we assume "X" to be
    correct.   Conversely, on the Brady challenges, the key question
    posed is whether the unproduced evidence "could reasonably be taken
    to put the whole case in such a different light as to undermine
    confidence in the verdict."    United States v. Avilés-Colón, 
    536 F.3d 1
    , 19 (1st Cir. 2008) (internal quotation marks omitted).
    Answering this question requires that "[w]e evaluate the strength
    -4-
    of the impeachment evidence and the effect of its suppression in
    the context of the entire record."        
    Id. (alteration in
    original)
    (internal quotation marks omitted).          Thus, in the hypothetical
    example posed above, and with omitted evidence in the form of
    documents calling into question the credibility of the prosecution
    witness, we do not assume "X" to be correct; rather, we consider
    the evidence as a whole to gauge the impact that the documents
    would likely have had on the jury in weighing the evidence.
    The appellants were tried before a jury in October and
    November of 2009.      The prosecution's witnesses told of a wide-
    ranging conspiracy led by Ramos and staffed by his cadre of
    "lieutenants" (including Omar), "sellers" (including Sandra), and
    "runners" (including Sonia).
    The prosecution's star witness was Harry Smith Delgado
    Cañuelas ("Delgado").        Upon his release from prison in 2004,
    Delgado moved to the Victor Berríos Public Housing Project ("Victor
    Berríos") in Yabucoa, Puerto Rico. He testified that brothers Alex
    and Ramiro Nazario controlled heroin sales at Victor Berríos in
    2004,    whereas   Ramos   controlled   crack,   cocaine,   and   marijuana
    distribution.      Delgado said that, while working for the Nazario
    brothers, he learned where Ramos's organization hid its drug
    inventory, and he stole a large packet (a "muerto") of Ramos's
    drugs.    Ramos, he said, suspected him of taking the "muerto," and
    hired Delgado with the intent to later kill him after Ramos
    -5-
    purchased control of the heroin drug point from the Nazario
    brothers in 2005.        But after seeing how effectively Delgado was
    "building up" heroin sales under Omar's supervision, Ramos decided
    Delgado was more valuable to him alive than dead.
    Delgado explained that his role as a lead administrator
    at Victor Berríos gave him an insider's view of the organization's
    leadership.       Omar    and   two     other    defendants      acted    as   "order
    sergeants" in carrying out Ramos's commands whenever a problem
    arose at a Ramos-owned drug point.                   Delgado also recounted how
    Ramos kept tabs on competitors who sought to establish other drug
    points near Victor Berríos.
    Delgado's additional role as a seller provided insight
    into    the   organization's       day-to-day        operations    as    well.      He
    testified that Sonia was a "runner" for the Victor Berríos drug
    point.    When a seller's supply ran low, Sonia would fetch drugs
    from Ramos's inventory and deliver them to the seller.                           After
    another individual finished tallying drug sales, Sonia stashed away
    the proceeds until one of Ramos's lieutenants picked up the money.
    Sandra, meanwhile, served as both a runner and a seller of cocaine,
    crack, and marijuana.           Two other cooperating witnesses, whose
    testimony is described below, painted a similar picture of Sandra's
    role.
    Delgado    claimed      that     his    employment       with    Ramos's
    organization     continued      until    2007,       when   he   was   arrested    for
    -6-
    attempted    murder     in   Yabucoa.       Delgado      soon   thereafter        began
    cooperating with the government.
    Xiomara Berríos-Rojas ("Xiomara") was the government's
    second cooperating witness who claimed to have been a member of the
    conspiracy.     Xiomara testified that she began working for Ramos's
    organization     at    Victor     Berríos     in   or    around     2004,    selling
    marijuana,    crack,     and    cocaine.       She      testified    that    certain
    notebooks, seized by the police from an apartment belonging to one
    of Ramos's lead bookkeepers at Victor Berríos, included "tallies"
    reflecting the accounting of drug sales.                 Xiomara also testified
    that a video depicting Sandra and Sonia at Victor Berríos showed
    them dispensing crack, although no drugs were visible in the
    footage.    And she agreed with Delgado's testimony that Sonia was a
    "runner" for Ramos.
    The third cooperating witness to testify was Andy Marcano
    ("Andy"). Andy, like Xiomara, was a "runner." He delivered heroin
    and other drugs to various drug points, including Victor Berríos.
    Andy said that he also accompanied Ramos and his lieutenants when
    it became necessary to threaten competitors or discipline the
    organization's members.
    Andy     explained    that     Omar     cooked     heroin      for    the
    organization and acted as one of Ramos's lieutenants.                             After
    preparing the heroin, Omar gave it to Andy or another runner, who
    then delivered it to sellers such as Delgado.
    -7-
    Central to the defendants' (in particular, Ramos's) trial
    strategy was an attempt to impeach Delgado, Xiomara, and Andy by
    suggesting that they engaged in a coordinated effort to fabricate
    their testimony. Leading up to the trial, the three witnesses were
    housed in a unit for cooperators within the Metropolitan Detention
    Center (MDC) in Guaynabo, Puerto Rico.              Within the cooperators'
    unit, the men were located in section 4-C ("4-Charlie"), and
    Xiomara resided in section 3-C, "right below" 4-Charlie.               Xiomara
    admitted it was possible for the cooperators to talk to prisoners
    in other cells through the plumbing system by removing water from
    each cell's toilet bowl.
    On the stand, all three witnesses admitted speaking to
    each other at MDC, but they flatly and firmly denied discussing
    anything involving the instant case.              Asked by Ramos's counsel
    whether   he   discussed   the   case   with      Andy,   Delgado   responded:
    "No . . ., from the beginning when I arrived [at 4-Charlie] in
    2007, the order is that you cannot talk about the cases with
    anybody, anybody, nobody, nobody." Similarly, while admitting that
    she spoke to Delgado "on several occasions," Xiomara denied ever
    speaking to him after she began cooperating with the government,
    and she also denied that Delgado convinced her to testify or that
    they discussed their testimony with one another.                    Andy, too,
    admitted to speaking to Delgado at 4-Charlie.              But when asked on
    cross-examination    whether     he   "at   any    time   discuss[ed]    [his]
    -8-
    testimony or the facts of this case with Harry Delgado," Andy
    replied, "No.     It is totally prohibited to us to talk about the
    case."
    One might think that in this case charging a conspiracy
    covering so much time, geography, and wrongdoing, the prosecution
    (perhaps with the assistance of the cooperating witnesses) would
    have offered a great deal of other evidence that did not depend on,
    and   indeed    corroborated,    the   testimony    of   its   cooperating
    witnesses.     One would be wrong.        The government points us to no
    such evidence of any significant probative value, especially as it
    might bear on Ramos and Omar.
    Government agents did explain how they set up secret
    cameras, and seized computers, cell phones, and notebooks. They
    also explained how they caught a number of other individuals red-
    handed at Victor Berríos.       None of this evidence, though, directly
    implicated Ramos or Omar, and none of the other individuals who
    were implicated testified.
    After a thirteen-day trial, the jury found Ramos and Omar
    guilty on all six counts charged in the superseding indictment.
    The government dismissed the firearms charge against Sonia and
    Sandra prior to jury deliberations, but the jury returned a guilty
    -9-
    verdict against those two appellants as to the five remaining drug
    trafficking counts.3
    At the close of their respective sentencing hearings, the
    district court sentenced the appellants to the following terms of
    imprisonment:   Sonia, 151 months; Sandra, 240 months; Omar, 480
    months; Ramos, life imprisonment.       Each of the four appellants
    timely appealed their convictions and sentences, but intervening
    events arising from the severed counts of witness tampering against
    Ramos delayed their appeals from reaching this Court for several
    years.
    II.    Ramos and Omar's Brady Claims
    At some unspecified time before the trial of this case,
    Delgado sent the lead prosecutor a handwritten letter that was, on
    its face, a document that the prosecutor was required to disclose
    to defense counsel prior to trial.      The prosecutor did not make
    this disclosure.   Instead, she recounts that she put a copy of the
    letter in her file for the separate trial on the witness tampering
    charges against Ramos, and forgot about it even as she tried this
    case in which Delgado was, in her words, her star witness.      She
    then came across the letter after the trial of this case when
    preparing to try the witness tampering case.    The prosecutor also
    managed not to provide defense counsel prior to the verdicts a
    3
    The jury also found all four appellants guilty of the
    forfeiture counts.
    -10-
    series of notes Delgado kept, or notes taken by FBI agents during
    their interviews with another indicted co-conspirator, Gabriel
    Medina-Pabon ("Medina").        The     belated production of these
    materials set off a series of post-trial evidentiary hearings and
    motions by Ramos, Omar, and Sandra.          The district court, in four
    separate opinions issued between 2010 and 2013, rejected the
    appellants' various arguments for a new trial based on the belated
    productions.    Those four opinions provide a detailed account of
    each of the hearings conducted by and motions submitted to the
    district court.    See United States v. Ramos-González, 
    747 F. Supp. 2d
    280, 284—89 (D.P.R. 2010); United States v. Ramos-González, No.
    07-318, 
    2011 WL 2144215
    , at *1—2 (D.P.R. May 31, 2011); Opinion &
    Order, ECF No. 2648 at 1—3, July 30, 2012; Opinion & Order, ECF No.
    2972 at 1—6, August 9, 2013.            We describe the details of the
    withheld evidence and the district court's reasoning.
    A.   The Withheld Evidence
    1.      Delgado's Letter to the Prosecutor
    The   evidence   of    Delgado's    letter   to   the   prosecutor
    consisted of two photocopied pages of handwritten text.                  The
    certified translation of the letter states as follows:
    To: The Prosecutor Dina Avíla Jímenez
    From: The best cooperator, Harry S. Delgado
    Hello!
    I hope under God Almighty that when you
    receive the foregoing in your hands, you enjoy
    perfect health together with your co-workers
    -11-
    and relatives. It is my best wish from the
    bottom of my heart.
    About me, I tell you that [illegible], I am
    well health-wise.
    I will start by saying that this is to let you
    know to please remember these 2 things, the
    first is that Jeanette4 is on probation and
    before she leaves the country, to clarify that
    point of view, because otherwise, they'll deem
    her as a fugitive and they may take away my
    daughters, and that would kill me, please
    clarify this thing of the probation first; and
    the second thing, I need an order from the
    Judge so that when they transfer me Jeanette
    can visit me, remember that I am not legally
    married, and to get visits you have to fill in
    a paper that you have to put your home and the
    criminal record and it is not convenient for
    any jail to know where Jeanette lives, what we
    want is that the least they know, the better,
    please help me, I am doing everything for my
    daughters and Jeanette. I need you to help me
    please. I promised you, the last time we saw
    each other, to do everything you said and I
    have done it to the point that you know how
    this has gotten, we have more than we
    expected, more evidence and more strength for
    the case, I hope you can help me, I will
    The photocopy of the letter is cut off after "I will" at
    the end of the letter's second page.    The prosecutor reports that
    when she re-discovered the letter after the trial, she asked the
    FBI agents to "go through each . . . folder or envelope to see if
    they could find the original," but they were unable to find it.
    Ramos-González, 
    747 F. Supp. 2d
    at 286—87.      The prosecutor said
    that the agents could not find any other materials related to the
    letter, and she denied destroying any part of the letter herself or
    4
    Jeanette was Delgado's conjugal partner.
    -12-
    instructing the agents to destroy part of the letter. The district
    court was unable to definitively determine whether additional pages
    were missing from the letter and, if so, how such pages may have
    disappeared.     
    Id. at 284.
    2.     Delgado's Toilet Conversation Notes
    Delgado made notes of two conversations with Andy and
    Medina on the night of December 9, 2008, one at 8:57 p.m. and the
    other at 9:18 p.m.        
    Id. at 287.
       Those conversations took place
    through the "toilet system" at MDC, 
    id. at 287,
    where, as we
    mentioned above, Delgado, Xiomara, Andy, and Medina were all
    incarcerated leading up to the drug trafficking trial.
    The notes reflect that Andy and Medina attempted to curry
    favor   with    Delgado   (who   they   presumably   knew    was   the   lead
    cooperator) and to downplay their own roles in the conspiracy.
    According to the notes, Medina said: "Look [Delgado], I'm calling
    to tell you that I am cooperating in the case with the prosecutor
    and I know you are getting [Xiomara] ready. . . .           Andy and I are
    going to cooperate, I already started to cooperate."           Medina then
    questioned Delgado as to why the government was "plac[ing] [him] at
    the [drug] point when you know that I wasn't working there."             Andy
    also denied being an "enforcer."        Delgado replied:     "You very well
    know that you were dealing," and proceeded to remind Medina of a
    time when he assisted Delgado with storing guns.            The rest of the
    -13-
    conversation basically reiterated Medina's pleas to Delgado to
    treat him well in prison.
    Delgado's notes also relate a later conversation between
    Delgado and Andy that had a similar tenor to Delgado's conversation
    with Medina.     Andy asked why the government had him "down as an
    enforce[r]." Delgado replied: "Listen, you know that I know about
    your situation, and to tell you a little something, do you remember
    the meeting in Caguas, where you, [Ramos], Manolo, [Bam Bam],
    Eddie, Omar, and the others were there?"         Andy said: "Yes, yes,
    yes, it's true, but I'm going to cooperate and I'm going to bring
    down all of those who stayed behind," and, "What I want is that
    when we go up there, for us not to be enemies, but friends, and be
    only [one], so we can help each other."       They then agreed to talk
    to each other again the following day at 8:00, but there are no
    notes of any subsequent conversations on the record. At some point
    the   prosecutor,   according   to   her   testimony   at   a   post-trial
    proceeding, "scolded" Delgado for making the notes after he turned
    them in and ordered him to stop making them.
    3.   "Rough Notes" of Interviews with Medina
    FBI agents interviewed Medina three times in November and
    December 2008 about the drug conspiracy, but Medina never testified
    at trial.    The prosecutor turned over the FBI "302 Reports" (the
    FBI's official notes of what was said during the interviews) prior
    to trial, but she withheld "rough notes" transcribed by one of the
    -14-
    interviewers, FBI Special Agent Carlos Barreiro.               The rough notes
    were finally disclosed to defense counsel in September 2012 at one
    of the post-trial evidentiary hearings involving allegations by
    Ramos and Omar that the government intimidated Medina, causing him
    not to testify on behalf of Ramos at an earlier post-trial hearing.
    These notes, including the Spanish version and English translation,
    span 121 pages of our appellate record.
    The   rough    notes'    content     largely    overlaps      with   the
    information in the disclosed 302 Reports.                However, Omar, whose
    motion for a new trial on the basis of these notes was joined by
    Ramos, argued before the district court that the rough notes
    contained various new pieces of exculpatory impeachment evidence.
    For example, the notes stated that Andy and another individual
    "tapped    Xiomara's     [phone]    line   and   listened     to    conversations
    between her and [Delgado]" in prison.               Medina also omitted any
    mention of Omar's involvement within the time period in the
    indictment (the only mention of Omar concerned events occurring in
    1999),    which   Omar    argued    below    and    on     appeal    is   "totally
    exculpatory" as to him.       And Medina inferred that Delgado murdered
    a man known as "Barquilla," even though Delgado denied having
    anything to do with that murder while on the stand.
    B.   The District Court Opinions
    In a series of four detailed opinions, the district court
    rejected    all   arguments   that    the    above-described        evidence     was
    -15-
    sufficiently impeaching or exculpatory to warrant a new trial. The
    court concluded that, had the defense possessed the evidence prior
    to trial, none of it would have had a "reasonable probability" of
    changing the result.5      In the first opinion, the court made a
    preliminary finding that "the evidentiary hearing allowed the Court
    to gauge [the prosecutor's] testimony as credible and supportive of
    her avowal of good faith in belatedly disclosing the evidence by
    reason of inadvertence."    Ramos-González, 
    747 F. Supp. 2d
    at 287.
    As for the evidence's materiality, the court found that:
    The evidence . . . [was] principally aimed at
    impeaching Delgado's credibility and bias in
    favor of the government, issues that were
    already opened at trial and closed shut by the
    jury. . . . Beyond the smokescreen of factual
    allegations attacking Delgado's credibility,
    which were in large part previously decided by
    the jury, Defendants have not pointed to a
    single piece of material evidence that
    undermines the guilty verdicts, especially
    when substantial evidence corroborates their
    participation   in    the   drug   trafficking
    conspiracy.
    
    Id. at 292.
    With regard to Delgado's letter, the district court
    pointed out that the defendants had in their possession, before
    trial, information showing Delgado's receipt of benefits from the
    government, including assistance with relocating his family.   
    Id. at 293.
      Moreover, Delgado admitted on direct examination that his
    5
    We discuss the applicable legal standard in greater detail
    in Part 1.C, below.
    -16-
    family received close to $10,000 from the FBI for his cooperation,
    and the court warned the jurors that Delgado's receipt of such
    benefits could affect his veracity and should be considered in
    judging his credibility.      
    Id. Therefore, the
    district court
    concluded that the letter, "stripped to [its] bare essentials,
    . . . say[s] nothing more than what has already been said about
    Delgado at trial" and the attempt to impeach Delgado with the
    letter could "only be described as cumulative."      
    Id. at 294.
    Similarly, the court found that Delgado's conversations
    with Andy and Medina as reflected in Delgado's notes fell "into the
    same general category of cumulative or collateral impeachment
    evidence failing to create a reasonable probability of acquittal."
    
    Id. at 294.
      The court explained that the notes "simply reflect
    conversations by two co-defendants who were either contemplating
    cooperating   or   already   decided    upon   cooperating    with   the
    Government.   In essence, [Andy] and Medina [were] attempting to
    exculpate themselves, not Defendants, from playing major roles in
    the drug conspiracy, and are attempting to curry favor with Delgado
    . . . such that he would treat them fairly when they would arrive
    and reside together at the cooperator's [sic] unit."         
    Id. at 295.
    The court "fail[ed] to see how the conversations [between the
    cooperators] were clearly related to the drug trafficking charges
    in the sense that the cooperators were discussing any key material
    factual allegations relating to [the appellants'] participation in
    -17-
    the conspiracy and guilt."     
    Id. at 296.
        Thus, this evidence, too,
    was "collateral because [it did] not exculpate Defendants in any
    way, and, [it was] cumulative because the fact that the cooperators
    spoke in prison . . . was subject to extensive cross-examination at
    trial."   
    Id. With respect
    to the rough notes (which were not produced
    until 2012, two years after the court issued its first post-trial
    opinion),    the   court   again   concluded   the   evidence    was   both
    collateral and cumulative. As a general matter, Medina's testimony
    at a 2012 hearing for the government's alleged prosecutorial
    misconduct, while still inculpating the defendants, conflicted with
    many of the statements reflected in the rough notes.             Thus, the
    probative force of his pre-trial statements was weak, and the notes
    of those interviews did "little, if nothing at all, to undermine
    the confidence of the verdict against the defendant."           In response
    to Omar's claim that the absence of any mention of his involvement
    in the rough notes during the period included in the indictment was
    "totally exculpatory" to him, the court concluded that such an
    absence was at best neutral and therefore immaterial.
    Finding that "the undisclosed evidence was neither new or
    [sic] exculpatory, but was collateral and cumulative," and that
    -18-
    "the government did not engage in any misconduct," the court denied
    the defendants' final motion for a new trial.6
    C.   Standard of Review for the Denial of a New Trial
    On appeal, only Ramos and Omar renew their contentions
    that the withheld evidence warranted a new trial, so we evaluate
    the Brady issue solely with respect to them.7
    The appellants brought their new trial motions under
    Federal Rule of Criminal Procedure 33, which provides that "[u]pon
    the defendant's motion, the court may vacate any judgment and grant
    a new trial if the interest of justice so requires."   We review the
    district court's denial of a Rule 33 motion for "manifest abuse of
    discretion."   
    González-González, 258 F.3d at 20
    .
    As this circuit has previously explained, motions for a
    new trial based on newly discovered evidence generally require a
    6
    The court's denial of the defendants' motion to dismiss the
    indictment due to the government's alleged prosecutorial misconduct
    is not at issue in this appeal.
    7
    Sandra's trial counsel joined Ramos and Omar in petitioning
    the district court for a new trial after the prosecutor turned over
    Delgado's letter and notes in 2010. Her appellate counsel has not
    renewed this claim on appeal. Counsel was clearly aware of his
    ability to adopt a co-appellant's arguments in a consolidated case
    pursuant to Federal Rule Appellate Procedure 28(i), since he
    reserved his right to do so in Sandra's opening brief. But counsel
    never filed a reply brief after the court granted him an extension,
    nor did he make a motion to adopt the other appellants' arguments.
    Sonia did not make a motion for a new trial below and does not
    attempt to piggyback on her co-appellants' motions on appeal, even
    though her appellate counsel was clearly aware of the Brady issue,
    since she is also representing Ramos in this appeal.        Sonia's
    opening brief includes a footnote referencing Delgado's letter but
    makes no argument in relation to it.
    -19-
    four-pronged    showing   that:      "(1)    the    evidence   was   unknown   or
    unavailable to the defendant at the time of trial; (2) failure to
    learn of the evidence was not due to lack of diligence by the
    defendant; (3) the evidence is material, and not merely cumulative
    or impeaching; and (4) it will probably result in an acquittal upon
    retrial of the defendant."        
    Id. (quoting United
    States v. Wright,
    
    625 F.2d 1017
    , 1019 (1st Cir. 1980)).              However, when the basis for
    the motion is that the government failed to disclose evidence
    required   to   be    disclosed    under      Brady,    either   willfully     or
    inadvertently,   we    apply   the    more    defendant-friendly       Kyles   v.
    Whitley standard to the test's third and fourth prongs.               See Kyles
    v. Whitley, 
    514 U.S. 419
    , 434 (1995); United States v. Josleyn, 
    206 F.3d 144
    , 151—52 (1st Cir. 2000).            Instead of requiring that the
    defendant show that an acquittal would have "probably" resulted had
    the material been produced, we require only that the defendant show
    a "reasonable probability" that had the government disclosed the
    evidence prior to trial, the result of the proceeding would have
    been different. 
    González-González, 258 F.3d at 20
    . Answering that
    question requires that we determine whether a trial held in the
    absence of such evidence can be described as a trial that can
    produce "a verdict worthy of confidence."              
    Id. (citing Kyles,
    514
    U.S. at 434).        "This somewhat delphic 'undermine confidence'
    formula suggests that reversal might be warranted in some cases
    even if there is less than an even chance that the evidence would
    -20-
    produce an acquittal."    Conley v. United States, 
    415 F.3d 183
    , 188
    (1st Cir. 2005) (internal quotation marks omitted).
    D.   A Preliminary Note
    We pause here to acknowledge that this is not the first
    time our circuit has referenced the district court's 2010 opinion
    rejecting Ramos and Omar's request for a new trial based on
    Delgado's letter and toilet conversation notes.8   In United States
    v. Ramos-González, 
    775 F.3d 483
    , 509—10 (1st Cir. 2014) (which we
    will call "the possession case" for purposes of this discussion),
    we affirmed Ramos's conviction for a separate drug offense.9    One
    of Ramos's arguments in his appeal from the possession case
    conviction was that the indictment against him should have been
    dismissed, in part because the prosecutor also failed to timely
    disclose certain 302 Reports of interviews with Ramos's arresting
    officers.   
    Id. at 491–92.
      To buttress his claim of prosecutorial
    misconduct in that case, Ramos pointed out that the prosecutor in
    that case was the same one who also failed to timely disclose the
    above-described letter and notes from Delgado in the instant
    conspiracy case.    
    Id. at 492.
        Ramos urged us to find that the
    8
    Because the prosecutor did not disclose the rough notes
    until 2012, they were not addressed by the district court until
    2013.
    9
    We also remanded the possession case for resentencing in
    light of the district court's erroneous application of the career
    offender enhancement under the sentencing guidelines. 
    Id. at 487,
    503–08.
    -21-
    prosecutor's actions, considered cumulatively in the two cases,
    amounted to a "recurrent pattern of concealment and deception" and
    a   "flagrant   disregard   for   [his]   constitutional   rights"   that
    warranted a dismissal of the indictment in the possession case.
    
    Id. We rejected
    that argument.        After explaining why the
    prosecutor's failure to disclose the 302 Reports in the possession
    case itself did not constitute "an extreme case of prosecutorial
    misconduct," 
    id. at 493,
    we addressed Ramos's argument based on the
    cumulative conduct in the two cases.       In so doing, we "express[ed]
    concern about the repeated nondisclosure of evidence" in the
    prosecutions against Ramos and noted that "[t]he United States
    Attorney's Office should develop procedures to avoid repeating the
    lapses that occurred in these cases."       
    Id. at 494.
       Nevertheless,
    we affirmed the verdict in the possession case and made the
    following statement regarding the ruling in this case that is now
    the subject of this direct appeal:
    As an initial matter, the district court in
    the conspiracy case took the defendants' Brady
    claims seriously, conducted an evidentiary
    hearing, and wrote a thoughtful opinion
    explaining why the alleged violations there
    did not warrant a new trial.       Given such
    careful treatment, that court's judgment that
    no constitutional violation occurred in the
    trial over which it presided is owed deference
    by both the district court in the instant case
    and by us on appeal.
    
    Id. at 493–94
    (internal citation omitted).
    -22-
    So we must first ask whether the above-quoted language
    dictates the resolution of the Brady issue on this direct appeal.
    For the following reasons, we think not.
    First, the precise question posed in the possession case
    trained on the conduct and good faith of the prosecutor.                   The
    argument posed was that misconduct in one case supported a finding
    of misconduct in another, or that two errors could not be explained
    as innocent.     To reject that argument, it was sufficient to defer
    to the district court's finding that the prosecutor did not act in
    bad faith.      As we will explain, there is no need to revisit that
    finding on this appeal.
    Second, and relatedly, in its collateral discussion of
    the district court ruling in the instant case, the prior panel
    (which included one of the judges on this panel) simply did not
    have the complete record.          This appeal in this case is the first
    appellate opportunity to examine the above-described Brady material
    and to analyze its potential effect on the appellants' drug
    conspiracy convictions.        We re-emphasize, and this is critical,
    that the dispositive inquiry in determining whether a defendant is
    entitled   to    a   new   trial   under   Brady   is   whether   there   is   a
    "reasonable probability" that the newly discovered evidence would
    result in an acquittal in this case.           Since we have never before
    looked at the full record to determine whether Delgado's letter and
    notes would have any effect on the jury's finding in the instant
    -23-
    conspiracy   case,      our   deferential       statement    that    the   district
    court's   2010    opinion     was   "careful"     and   "thoughtful"       contains
    limited, if any, value to us in deciding Ramos and Omar's claims.
    We proceed with our analysis.
    E.   Analysis
    The district court did indeed recite with care and
    thought the correct standards and, as we have summarized above, it
    issued detailed opinions rejecting the appellants' arguments.
    Nevertheless,     we    disagree    with   the    district    court's      ultimate
    conclusion that the withheld evidence, considered cumulatively,
    lacked sufficient materiality to create a "reasonable probability"
    of acquittal had it been disclosed.               Our disagreement is strong
    enough to overcome the considerable deference we must yield to a
    trial court on such decisions.
    We begin with the well-established principle that, under
    Brady, the government has an "affirmative duty to disclose evidence
    favorable    to   a    defendant,"    be   it    exculpatory    or    impeachment
    evidence.    
    Kyles, 514 U.S. at 432
    —33.           However, "[w]e do not . . .
    automatically require a new trial whenever a combing of the
    prosecutors' files after the trial has disclosed evidence possibly
    useful to the defense but not likely to have changed the verdict."
    United States v. Dumas, 
    207 F.3d 11
    , 15 (1st Cir. 2000) (quoting
    Giglio    v. United States, 
    405 U.S. 150
    , 154 (1972) (internal
    quotation marks omitted)).          The following guidance on materiality
    -24-
    compiled   from   Supreme      Court   and    First   Circuit   precedent   is
    particularly instructive with respect to the newly discovered
    evidence in this case:
    In analyzing whether there was a Brady
    violation, we evaluate the strength of the
    impeachment evidence and the effect of its
    suppression in the context of the entire
    record to determine its materiality.       The
    import of withholding evidence is heightened
    where the evidence is highly impeaching or
    when the witness' testimony is uncorroborated
    and essential to the conviction. . . .      We
    must grant a new trial if, after assessing the
    significance of the non-disclosed evidence in
    the context of trial, the favorable evidence
    could reasonably be taken to put the whole
    case in such a different light as to undermine
    confidence in the verdict.
    
    Avilés-Colón, 536 F.3d at 19
      (internal    quotation   marks    and
    citations omitted) (quoting, inter alia, Strickler v. Green, 
    527 U.S. 263
    , 290 (1999) and 
    Kyles, 514 U.S. at 435
    ).
    Applying this test, we observe, first, that the testimony
    of the three cooperating witnesses--especially Delgado--was both
    essential to the convictions and uncorroborated by any significant
    independent evidence.       Indeed, the absence of such evidence is so
    marked and surprising in view of the resources devoted to the
    investigation and the availability of three turned conspirators
    that it could reasonably cause the factfinder to be dubious about
    the witnesses' claims. This is therefore a case in which the Brady
    material that was not produced need not be "highly impeaching" in
    -25-
    order to require that the verdict be reversed.            
    Avilés-Colón, 536 F.3d at 19
    .
    Delgado was the star witness.         The prosecutor told us so
    much at oral argument and emphasized Delgado's testimony throughout
    her closing argument at trial.          His direct examination lasted an
    entire day, and his cross, re-cross, and re-direct examination
    lasted a day and a half more.          On cross, defense counsel worked
    through   the   usual   litany   of    attacks   one    might   make   on   any
    cooperating witness.      Delgado parried any suggestions that his
    testimony was orchestrated with that of the other witnesses.                In
    fact, he denied even talking about the case with them, telling the
    jury that to do so was against the rules.         So, too, did those other
    two cooperating witnesses firmly deny a basic premise of the
    defense: that they coordinated their testimony.
    Had defense counsel possessed Delgado's notes, counsel
    could have either shown Delgado and the others to have perjured
    themselves, and/or forced them to admit that they had at the very
    least compared prospective testimony with one another.             The notes
    indicate that Delgado was encouraging Andy and Xiomara to testify,
    and recount in detail at least one conversation where Delgado
    "reminded" Andy about a meeting involving Ramos and Omar, which a
    jury could have interpreted as Delgado telling Andy what to say.
    Similarly, the rough notes show that Andy knew that Delgado and
    Xiomara were talking through the pipes.                It was not just the
    -26-
    defense who believed the potential for the cooperators to talk
    about the case in prison jeopardized the government's chances of a
    conviction.10    The prosecutor elicited testimony from Andy on re-
    direct that suggested male and female prisoners could not talk to
    each other at the prison.11
    Delgado's letter to the prosecutor is probative for a
    different reason.      Although it contains no fact directly at
    variance with his testimony,12 its overall tone turns it into what
    could clearly have been a focus of a defendant's closing.    In the
    10
    In line with Supreme Court precedent, we decide whether the
    newly discovered "evidence is material . . . to guilt . . .
    irrespective of the good faith or bad faith of the prosecution."
    
    Brady, 373 U.S. at 87
    ; see also 
    Kyles, 514 U.S. at 432
    .
    11
    We refer to the following exchange:
    Prosecutor:    [Defense counsel] asked you
    whether you and Harry had discussed the facts
    of this case or the case about your testimony.
    Andy: Yes, he asked me that question.
    Prosecutor: Sir, what kind of gender inmates
    are in Four Charlie?
    Andy: We are all males.
    Prosecutor: So where is Xiomara located?
    Andy: The 3 C unit.
    Prosecutor: So you and Harry do not share a
    same unit with Xiomara?
    Andy: No.
    12
    The letter did contain at least one "new" fact that the
    defendants lacked at trial but that they could have used for
    impeachment purposes:    Delgado's girlfriend Jeanette, who he
    references in the letter, was on probation while Delgado was
    cooperating. Delgado's letter suggests that the government was
    allowing Jeanette to travel out of Puerto Rico with Delgado's
    children due to his cooperation.
    -27-
    letter,   Delgado    presents    himself    as   the   prosecutor's    "best
    cooperator";   a    fawning,    desperate   supplicant    willing     to   "do
    everything [the prosecutor] said" and eager to point out how much
    assistance he was providing her.          Importantly, the fact that the
    last part of the letter appears to have been destroyed--the part
    where it seems he was saying what he would do--heightens greatly
    its probative value, both raising an inference of spoliation,
    see United States v. Laurent, 
    607 F.3d 895
    , 902 (1st Cir. 2010),13
    and providing a powerful tool in the hands of any good trial
    counsel to call into question the credibility of both the key
    witness and, implicitly, the lead prosecutor.14
    13
    Omar argued below and on appeal that the prosecution's
    failure to preserve the entire letter supported a new trial under
    Arizona v. Youngblood, 
    488 U.S. 51
    , 58 (1988) (holding that bad
    faith destruction of evidence constitutes a due process violation).
    In 
    Dumas, 207 F.3d at 15
    , we explained that in order to obtain a
    new trial on a Youngblood-style destruction of evidence rationale,
    "[t]he defendant must show that, in failing to preserve the
    evidence, the government, (1) acted in bad faith when it destroyed
    evidence, which (2) possessed an apparent exculpatory value and
    which (3) is to some extent irreplaceable." While the district
    court's finding of no bad faith prevented a new trial based on the
    destruction of evidence rationale alone, the appellants likely
    would have been entitled to a spoliation instruction, allowing the
    jury to make an adverse inference that the destroyed evidence was
    favorable to the defense. See 
    Laurent, 607 F.3d at 902
    . Thus, the
    fact that the letter was partially destroyed is of import to our
    view of the withheld evidence's cumulative effect.
    14
    In noting that the apparently incomplete copy of the letter
    might suggest such an inference, we do not question the district
    court's conclusion that the non-production was unintentional. We
    do, however, repeat our concern that this United States Attorney's
    office, especially given its very heavy workload, appears to need
    better procedures for gathering and producing Brady materials.
    See 
    Ramos-González, 775 F.3d at 494
    .
    -28-
    In deeming all this evidence to be merely "cumulative,"
    the district court twice erred.   First, the district court relied
    heavily--at least twice--on its observation that the jury believed
    Delgado based on the evidence it did hear.      But this begs the
    question of whether the jury would have believed Delgado if it had
    also heard the omitted impeachment evidence. Second, the fact that
    the defense had some tools to attack Delgado's testimony hardly
    dismisses the potential of different tools as merely cumulative.
    If defense counsel had firm proof that a witness received $500 from
    the government, a letter confirming such a payment would be
    cumulative.   But a letter revealing another payment of $50,000
    would be cumulative only in the sense that its relevance pointed
    toward the same conclusion.   This type of cumulative evidence can
    be quite probative.
    Here, moreover, there was no other document or recording
    tending to prove that the witnesses were lying when they denied
    discussing their testimony with one another.   In so concluding, we
    have considered the district court's finding that "Ramos' camp was
    aware of conversations among co-defendants through the toilet at
    MDC prior to trial."    The district court based this finding upon
    Medina's post-trial testimony recalling a pre-trial meeting with
    Ramos's investigator in which he told the investigator that he
    heard Delgado and Xiomara discussing the case through the toilets.
    The investigator also testified and denied such a meeting ever
    -29-
    occurred, but the district court (despite finding Medina not to be
    a   credible       witness)    nevertheless   concluded      that   the   toilet
    conversations were not "unavailable" to Ramos under the first prong
    of Brady, and "thus, the motion for new trial must be denied[.]"
    See United States v. Del-Valle, 
    566 F.3d 31
    , 38 (1st Cir. 2009) (to
    establish      a    Brady     violation,   evidence   must    be    unknown   or
    unavailable to the defendant at the time of trial).
    We disagree with the district court's analysis.               First,
    a fact "known" to counsel remains entirely unknown to a jury unless
    counsel has admissible evidence of the fact.           There is no evidence
    that Medina would have been willing to testify at Ramos's trial or
    that he could have been so compelled.           Second, even if Medina had
    testified at trial, a swearing contest between Medina and Delgado
    is hardly the same in terms of impeachment value as notes written
    in Delgado's own hand. See United States v. Paladin, 
    748 F.3d 438
    ,
    446 (1st Cir. 2014) ("[S]uppressed impeachment evidence can be
    immaterial because of its cumulative nature only if the witness was
    already . . . impeached at trial by the same kind of evidence."
    (internal quotation marks omitted)).           And in this latter respect,
    it is noteworthy that in concluding that Medina's testimony lacked
    a reasonable probability of changing the result at trial, the
    district court opined that Medina was not a credible witness
    "considering the numerous inconsistencies in [his] statements." We
    also reiterate that our holding is based on the cumulative impact
    -30-
    of all of the newly discovered evidence, not solely the content of
    Delgado's alleged conversation with Xiomara.        See 
    Kyles, 514 U.S. at 420
    (explaining that the "disclosure obligation turns on the
    cumulative effect of all suppressed evidence favorable to the
    defense, not on the evidence considered item by item").
    We also recognize that, in some sense, the letter and
    notes were collateral because they did not directly bear on the
    factual evidence underlying the government's case. See 
    id. at 448;
    United States v. Beauchamp, 
    986 F.2d 1
    , 4 (1st Cir. 1993) ("A
    matter is considered collateral if 'the matter itself is not
    relevant in the litigation to establish a fact of consequence,
    i.e., not relevant for a purpose other than mere contradiction of
    the in-court testimony of the witness.'" (quoting 1 McCormack on
    Evidence § 45, at 169 (4th ed. 1992))).           Yet in another, very
    important sense, the evidence is anything but collateral because
    the possibility that the three linchpin witnesses colluded to
    fabricate incriminating testimony goes to the very core of this
    case and potentially compromises every piece of factual evidence
    the government had against Ramos and Omar.
    Semantics aside, here is where the rubber meets the road:
    This   was   a   case   that   surprisingly   pivoted   entirely   on   the
    credibility of Delgado and his two cohorts.        The unproduced Brady
    materials were the only evidence that would have eliminated the
    claim that the testimony was entirely uncoordinated, and the
    -31-
    Delgado letter would have provided a uniquely colorful tool for
    both attacking Delgado's motivation and raising the prospect that
    Delgado and the prosecutor were hiding something from the jury.
    Many members of the public would pause when told that a jury
    accepted Delgado's testimony--and convicted Ramos and Omar--without
    being shown any of these documents.             See Norton v. Spencer, 
    351 F.3d 1
    ,   9   (1st   Cir.    2003)   ("Confidence    in   the    outcome    is
    particularly      doubtful     when   the   withheld   evidence    impeaches    a
    witness whose testimony is uncorroborated and essential to the
    conviction." (internal quotation marks omitted)).15               We cannot say
    for sure what Delgado, Xiomara, and Andy would have said had they
    been confronted with this evidence on the stand (regardless of
    whether it was introduced on direct or cross-examination). Nor can
    we say that introduction of the withheld evidence would more likely
    than not have changed the verdict.               But the grasp of our own
    conviction need not reach so far.              Rather, under the applicable
    standard we need only find it to be "reasonably probable" that the
    15
    The lack of corroboration of the cooperators' testimony is
    a critical factor in helping us distinguish this appeal from other
    cases applying the same legal standard that came out the other way.
    See, e.g., 
    Paladin, 748 F.3d at 493
    (evidence of defendant's guilt
    was "overwhelming and did not depend on [the informant's]
    credibility"); United States v. Mathur, 
    624 F.3d 498
    , 505 (1st Cir.
    2010) (multiple witnesses gave first-hand accounts of being
    victimized by the defendant, and government introduced physical
    evidence corroborating defendant's guilt); 
    González-González, 258 F.3d at 18
    —19 (numerous other witnesses, who were not impeached by
    the newly discovered evidence, corroborated the impeached witness's
    testimony, and the government introduced voluminous incriminating
    documentary evidence of the defendant's guilt).
    -32-
    impeachment evidence would have caused the jury to acquit Ramos and
    Omar.    See United States v. Prochilo, 
    629 F.3d 264
    , 268 (1st Cir.
    2011).   These circumstances satisfy that test due to the combined
    impact of Delgado's solicitous and suspiciously incomplete letter,
    the toilet conversation notes that the prosecutor scolded Delgado
    for making, and the FBI's rough notes.          We therefore instruct the
    district court to grant Ramos and Omar's motions for a new trial.
    This   finding   disposes     of   Omar's   appeal,   since   any
    potentially reversible mistakes arising from the other trial and
    sentencing errors he alleges will be--at least temporarily--cured
    by our grant of a new trial.              Ramos, however, also makes a
    sufficiency of the evidence argument with respect to the aiding and
    abetting    counts   (counts   three    through    six).     A    successful
    sufficiency claim would oblige us to direct the court to dismiss
    those counts of the indictment, see Burks v. United States, 
    437 U.S. 1
    , 10—11 (1978)--a more severe remedy than a new trial--so we
    still must analyze that claim despite our ruling on the Brady
    issue.     As for Sonia and Sandra, neither of them pressed Brady
    claims before this Court.      We therefore proceed to address Ramos's
    sufficiency claim and each of Sonia and Sandra's assignments of
    error below.
    III.   Ramos's Sufficiency Argument
    Ramos moved for a judgment of acquittal on all counts
    based on the insufficiency of the evidence against him at the close
    -33-
    of the government's case, and he renewed that motion post-trial.
    See Fed. R. Crim. P. 29(a).        We review a district court's denial of
    a Rule 29 motion de novo, viewing the evidence in the light most
    favorable to the jury verdict and giving equal weight to direct and
    circumstantial evidence.       See United States v. Appolon, 
    695 F.3d 44
    , 55 (1st Cir. 2012).            "The verdict must stand unless the
    evidence is so scant that a rational factfinder could not conclude
    that the government proved all the essential elements of the
    charged crime beyond a reasonable doubt."              
    Id. (quoting United
    States v. Rodríguez-Vélez, 
    597 F.3d 32
    , 39 (1st Cir. 2010)).
    On appeal, Ramos argues only that the trial evidence was
    insufficient to prove the charges that he aided and abetted the
    possession    with   intent   to    distribute   heroin,     cocaine,   crack-
    cocaine, and marijuana.            When the government alleges that a
    defendant aided and abetted an illegal act, it must show that the
    "defendant participated in the venture and sought by [his] actions
    to make it succeed," United States v. Bristol-Martir, 
    570 F.3d 29
    ,
    39 (1st Cir. 2009) (alteration in original) (internal quotation
    marks   omitted),    and   that    he    "willingly   took   some   action   to
    facilitate" the crime, United States v. Bennett, 
    75 F.3d 40
    , 45
    (1st Cir. 1996).       Where the charges arise from a principal's
    possession with intent to distribute narcotics, "[k]nowledge of the
    particular controlled substance being . . . distributed is not
    necessary, and intent to distribute can be inferred from the
    -34-
    quantity of drugs involved."                 
    Bristol-Martir, 570 F.3d at 39
    (internal quotation marks omitted).
    As    we    have       explained,       the    prosecution's      case    was
    vulnerably    perched       on     the    testimony       of   cooperating   witnesses
    without   the    support       of   any    independent          corroboration.       That
    weakness,    though,        does    not    render    the       evidence   insufficient.
    Indeed, we have repeatedly held that even the "uncorroborated
    testimony of a cooperating accomplice may sustain a conviction so
    long as that testimony is not facially incredible."                       United States
    v. Cortés-Cabán, 
    691 F.3d 1
    , 14 (1st Cir. 2012) (collecting cases).
    Considering the evidence in the light most favorable to the
    government,      as    we    must    in    analyzing       an    attack    against    the
    sufficiency of the evidence, see 
    Bayes, 210 F.3d at 65
    —66, we
    conclude that a rational jury could have found Ramos guilty beyond
    a reasonable doubt on the aiding and abetting counts.                          Delgado,
    Xiomara, and Andy's trial testimony showed that, as the leader of
    the conspiracy, Ramos established the organization's primacy for
    all four types of drugs at Victor Berríos by "purchasing" control
    of the drug point from the Nazario brothers.                      He also made hiring
    decisions (such as his choice to retain Delgado as an administrator
    and seller at Victor Berríos and Andy as a "runner" at various drug
    points, including Victor Berríos), armed his employees (such as
    when he provided Delgado with a gun), and constructed a chain of
    command (by tapping Omar, José Manuel Zavala-Martí, and Bam Bam as
    -35-
    "order sergeants" who "dole[d] out" punishment to those who "failed
    at something").       Such high-level activities were no less helpful
    and intentional in furthering the organization's illegal objectives
    than the actions taken by the sellers and runners themselves.
    Ramos's sufficiency of the evidence argument therefore fails.
    IV.    Sandra Flores-Rivera's Arguments
    A.   "Other Act" Evidence
    Sandra first argues that she is entitled to a new trial
    because the district court committed error under Federal Rule of
    Evidence 404(b) by admitting testimony about "prior bad acts."           We
    begin by describing the complained-of evidence.
    Near the beginning of Xiomara's direct examination, the
    prosecutor asked her several questions aimed at lessening the blow
    of the defendants' anticipated impeachment attempts.           For example,
    the prosecutor elicited Xiomara's admission that she cut off her
    electronic bracelet while on bail, used drugs while on bail, lied
    to   her   parole     officer,   and     fought   another   prisoner   while
    incarcerated.   During this line of questions, the prosecutor asked
    Xiomara if she had "ever been involved in an incident regarding a
    knife."    Xiomara proceeded to explain that she was placed "in the
    hole" for seventeen days because prison officials discovered a
    homemade knife in a co-defendant's cell.           The following day, the
    prosecutor returned to this subject, and Xiomara clarified that it
    was Lauren Ortiz-Flores, Sandra's niece, in whose cell the knife
    -36-
    was found. Sandra was not mentioned in connection to this story at
    all.     On    cross-examination,       Sandra's    trial      counsel       elicited
    testimony that during the investigation about the homemade knife,
    prison   officials     found     a    sewing   needle     in     Xiomara's      cell.
    Prisoners were not allowed to have sewing needles, so this was
    another instance of Xiomara breaking prison rules.
    The second piece of evidence is a story told by Andy
    during his testimony.         Andy testified that Sandra and her sister
    Diana (also a co-defendant) got into a domestic dispute about a
    purported     love   affair    between    Sandra's       daughter      and   Diana's
    husband.      Andy, Omar, Zavala-Martí and three other members of the
    conspiracy traveled to Victor Berríos after hearing that Sandra and
    Diana had shot guns at each other as part of the dispute.                     Zavala-
    Martí warned Sandra and Diana that gunfire compromised the drug
    point because it would make the drug point "hot" and "attract
    cops."     He also threatened Sandra that if "he had to go back
    because of this sort of issue, . . . he was going to deal with
    her."
    Sandra concedes that she did not lodge a contemporaneous
    objection to the testimony about the homemade knife, the domestic
    dispute, or the shooting itself at trial.               We therefore review her
    claims for plain error, which means that we will only deem the
    testimony's      admission    to     justify   reversal     if    it    "seriously
    affect[ed]     the   fairness,       integrity,    or    public    reputation      of
    -37-
    judicial proceedings."     United States v. Olano, 
    507 U.S. 725
    , 732
    (1993) (internal quotation marks omitted); see United States v.
    Niemi, 
    579 F.3d 123
    , 128 (1st Cir. 2009) (reviewing defendant's
    forfeited 404(b) argument for plain error).
    Rule 404(b) provides that "[e]vidence of a crime, wrong,
    or other act is not admissible to prove a person's character in
    order to show that on a particular occasion the person acted in
    accordance with the character." Fed. R. Evid. 404(b)(1). The Rule
    expressly    provides   that   evidence    of   prior     bad    acts    "may   be
    admissible     for   another   purpose,     such     as    proving       motive,
    opportunity,    intent,   preparation,     plan,    knowledge,          identity,
    absence   of   mistake,   or   lack   of   accident."           Fed.    R.   Evid.
    404(b)(2).16
    Andy's account of the domestic dispute between Sandra and
    Diana exemplifies the type of prior bad act evidence that may be
    admitted for a purpose other than to show propensity.              See Fed. R.
    Evid. 404(b)(2) ("Permitted Uses").             The story illustrated how
    16
    Subparagraph (b)(2) of Rule 404 provides: "On request by a
    defendant in a criminal case, the prosecutor must: (A) provide
    reasonable notice of the general nature of any such evidence that
    the prosecutor intends to offer at trial[.]"       See also United
    States v. Tuesta-Toro, 
    29 F.3d 771
    , 774—75 (1st Cir. 1994)
    (discussing the specificity with which such a request must be made,
    and holding that a general request for exculpatory information was
    insufficient). Sandra argues that the prosecutor improperly failed
    to provide notice of the evidence, but she also admits that she did
    not request such notice. We therefore reject any implied argument
    that the prosecutor's failure to provide proper notice constituted
    reversible error.
    -38-
    high-ranking co-conspirators reprimanded lower-ranking members and
    ensured the drug-selling operation's continued success.                  Thus,
    while the domestic dispute itself was not relevant to Sandra's
    guilt, the incident in its entirety was probative in showing
    Sandra's participation in the conspiracy.            See United States v.
    Currier, 
    821 F.2d 52
    , 55 (1st Cir. 1987) ("[E]vidence of prior or
    contemporaneous uncharged conduct may be admissible to complete the
    story of a crime by proving the immediate context of events near in
    time and place."); United States v. Watson, 
    695 F.3d 159
    , 165 (1st
    Cir. 2012) (explaining that "the full weight of [the narrative]
    would be lost on the jury absent the introduction of some limited
    factual foundation"); United States v. Guerrero, 
    169 F.3d 933
    , 944
    (5th Cir. 1999) (noting that Rule 404(b) permits admission of
    evidence that explains the relationship between the parties).
    With respect to the homemade knife incident, the story
    had no direct connection to Sandra in the first place.                      Any
    inference   that   the   jury   may    have   made   due   to    the   familial
    relationship between Lauren and Sandra was too tenuous to attribute
    the "bad act" to Sandra in these circumstances, especially under
    plain error review.       We therefore need not decide whether the
    purpose of softening the blow of cross-examination would have been
    a proper non-propensity purpose under Rule 404(b).              Either way, it
    was at worst harmless.
    -39-
    Having     rejected     Sandra's        evidentiary     arguments,        we
    proceed to her sentencing challenges.
    B.    Sentencing Challenges
    The district court sentenced Sandra to twenty years'
    imprisonment with respect to count one, which represented the
    mandatory minimum term of incarceration for that count due to the
    drug quantities found by the jury, the proximity of the offense to
    a public housing project, and Sandra's prior felony drug offense
    convictions.    See 21 U.S.C. §§ 841(a)(1) and (b)(1)(A), 846, 851,
    and 860.   She was sentenced to 188 months for each of the four
    remaining counts, to run concurrently with count one and each
    other. Sandra challenges what amounts to a twenty-year sentence on
    two   bases,   both   of   which    butt      up    against    a   stone     wall    of
    controlling    precedent.        She   also       fails   to   direct   us    to    any
    indication in the record that she preserved her claims.                              We
    therefore review her two sentencing arguments on plain error
    review. See United States v. Dávila-González, 
    595 F.3d 42
    , 47 (1st
    Cir. 2010).
    Sandra      first       makes      a      broad     attack        on     the
    constitutionality of mandatory minimum sentences.                  This Court has
    already determined that "it is beyond cavil that Congress has the
    power to set statutory minimum and maximum sentences to which
    courts must adhere."       United States v. Gonzalez-Ramirez, 
    561 F.3d 22
    , 30 (1st Cir. 2009) (citing Chapman v. United States, 500 U.S.
    -40-
    453, 467 (1991)).     No subsequent case has called that conclusion
    into question.      Sandra's constitutional challenge to mandatory
    minimum sentences therefore fails to raise error, much less plain
    error.
    Sandra's   second   sentencing   challenge   is   based   on   a
    conflict she perceives between mandatory minimum sentences and the
    mandate in 18 U.S.C. § 3553(a) that sentences be "sufficient, but
    not greater than necessary, to comply with the purposes set forth"
    therein, including the nature and circumstances of the offense, the
    history and characteristics of the defendant, and other enumerated
    sentencing factors.      See 18 U.S.C. § 3553(a).       She argues that
    sometimes the mandatory minimum is greater than necessary to comply
    with those purposes.17   Thus, she says, we must rely on the rule of
    lenity to resolve the ambiguity in her favor, and (we assume)
    remand to the district court for a different sentence.
    We need look no farther than the text of section 3553
    itself to conclude that no such conflict exists.        Sections 3553(e)
    and (f) describe the limited situations in which a sentencing judge
    has the authority to impose a sentence below a statutorily mandated
    minimum.   A court may impose a lower sentence, for instance, when
    the government makes a motion to reduce the sentence due to the
    defendant's "substantial assistance" with an investigation or
    17
    Sandra fails to explain why her own sentence ought to be
    characterized as such.
    -41-
    prosecution.    18 U.S.C. § 3553(e).    There would have been no need
    for Congress to include these carve-outs had it not assumed that
    statutory mandatory minimums were generally applicable. Cf. United
    States v. Jimenez, 
    507 F.3d 13
    , 21 (1st Cir. 2007) (stating that
    the rule of lenity "only applies if there is a grievous ambiguity
    in the statute" (internal quotation marks omitted)).         Finding no
    ambiguity, reliance upon the rule of lenity is unnecessary, and we
    find no plain error in the district court's decision to subject
    Sandra to the statute's mandatory minimum sentence.
    V.   Sonia Flores-Rivera's Arguments
    A.   Sufficiency of the Evidence
    Like Ramos, Sonia moved for a judgment of acquittal based
    on the insufficiency of the evidence against her at the close of
    the government's case and post-trial.     See Fed. R. Crim. P. 29(a).
    Once again, we review the district court's denial of her Rule 29
    motion de novo, viewing the evidence in the light most favorable to
    the jury verdict.     See 
    Appolon, 695 F.3d at 55
    .
    In order to sustain a conviction for the drug conspiracy
    counts, "the evidence must show that: (1) [the] conspiracy existed;
    (2) the defendant had knowledge of the conspiracy; and (3) the
    defendant    knowingly    and   voluntarily   participated     in   the
    conspiracy."    United States v. Maryea, 
    704 F.3d 55
    , 73 (1st Cir.
    -42-
    2013).18   Here, the facially plausible trial testimony of Sonia's
    admitted co-conspirators provided sufficient evidence to sustain
    her conviction.     See 
    Cortés-Cabán, 691 F.3d at 14
    .          Sonia was
    identified by both Delgado and Xiomara as a "runner" for Ramos's
    organization.   Delgado also testified that he personally saw Sonia
    tallying drug proceeds at her apartment, and that he saw her take
    money from another conspirator and "stash" it until another member
    of the conspiracy retrieved the money.       Based on this testimony,
    the jury was entitled to conclude that Sonia, too, conspired to
    further the organization's objectives.
    B.   Prejudicial Variance
    Sonia   also   argues   that   even   if   the   evidence   was
    sufficient to prove her participation in the organization's drug
    trafficking at the Victor Berríos housing project, there was
    insufficient evidence tying her to the "larger conspiracy" charged
    in the indictment.    She points out that the indictment alleged a
    conspiracy taking place in Yabucoa, Caguas, and elsewhere in Puerto
    Rico, but the evidence of her direct participation was localized to
    Victor Berríos in Yabucoa.19
    18
    Sonia's opening brief did not include any argument on the
    aiding and abetting counts, and her reply brief simply claims that
    should the conspiracy convictions fall, so too will the aiding and
    abetting convictions. We find her argument as to the aiding and
    abetting convictions waived. See United States v. Zannino, 
    895 F.2d 1
    , 17 (1990).
    19
    The trial testimony showed that Ramos's employees operated
    in at least the cities of Aguas Buenas, Caguas, and Yabucoa.
    -43-
    We interpret Sonia's brief to argue that there was a
    prejudicial variance between the indictment and the trial evidence
    against her.   She groups this claim together with her sufficiency
    of the evidence argument, but she failed to alert the district
    court that she was claiming a distinct prejudicial variance error.
    Since we have previously stated that a prejudicial variance claim
    is often "a challenge to the sufficiency of the evidence," see
    United States v. Martínez-Medina, 
    279 F.3d 105
    , 113 (1st Cir.
    2002), we give Sonia the benefit of the doubt and assume without
    deciding that she preserved this argument by making her Rule 29
    motions below, because here the standard of review does not change
    the outcome.   Cf. United States v. Lyons, 
    740 F.3d 702
    , 716 (1st
    Cir. 2014).    Our review is therefore de novo, taking all of the
    evidence in the light most favorable to the government.        See
    
    Maryea, 704 F.3d at 73
    ; 
    Martínez-Medina, 279 F.3d at 113
    .
    "A prejudicial variance occurs when (1) the facts proved
    at trial differ from those alleged in the indictment; and (2) the
    error affects the defendant's substantive rights."     
    Maryea, 704 F.3d at 73
    .     Sonia is unable to satisfy either prong of our
    inquiry.
    With regard to the first prong, in order to be convicted
    of participating in a conspiracy, "each coconspirator need not know
    of or have contact with all other members, nor must they know all
    of the details of the conspiracy or participate in every act in
    -44-
    furtherance     of   it."      
    Martínez-Medina, 279 F.3d at 113
    .
    Furthermore, "[t]he jury may infer an agreement circumstantially by
    evidence of, inter alia, a common purpose (such as a purpose to
    sell illicit drugs), overlap of participants, and interdependence
    of various elements in the overall plan."           
    Id. at 113—14.
    The evidence before the jury showed not only that the
    drugs flowed from Ramos's inventory to multiple housing projects in
    different     cities,    but   that      Ramos's    lieutenants     enforced
    organizational discipline, punished thieves, and sought to exclude
    competitors     at   Ramos's   various    drug     points.     Runners   and
    lieutenants traveling from Caguas to Victor Berríos did not merely
    deliver drugs, but also checked on supply at each point of sale.
    Moreover, at least one witness--Andy--testified that he worked at
    multiple drug points owned by Ramos during his employment for the
    organization.    See 
    Rodriguez, 525 F.3d at 103
    (fact that different
    drug point owners used the same runners and sellers was evidence of
    a single conspiracy); cf. 
    Martínez-Medina, 279 F.3d at 114
    ("In a
    case where a common supplier is the sole link between diverse
    distributors, it may be more difficult to sustain a finding of
    common agreement, although even then one could be inferred by
    additional evidence--e.g., a finding that the various distributors
    depended on one another for the health of their own drug business."
    (internal citations omitted)).
    -45-
    Sonia also offers no coherent explanation for why she
    sustained any prejudice (prong two) due to her claimed lack of
    involvement in the organization's activities outside of the Victor
    Berríos drug point.           Simply put, the jury easily could have
    convicted   her   for    having     the   precise   role   charged    in   the
    indictment--running drugs and serving as an accountant for drug
    sales--without any consideration of events at other locations. See
    United States v. Twitty, 
    72 F.3d 228
    , 231 (1st Cir. 1995) ("[S]o
    long as the statutory violation remains the same, the jury can
    convict even if the facts found are somewhat different than those
    charged--so     long    as    the   difference   does   not   cause    unfair
    prejudice.").     Sonia does not, for example, contend that some of
    the drug types in the indictment related only to trafficking by
    others that occurred outside of Victor Berríos, or that sales made
    outside of that housing project were needed to achieve the charged
    quantity thresholds.         Cf. United States v. Dellosantos, 
    649 F.3d 109
    , 124 (1st Cir. 2011) (evidence failed to show that defendants
    participated in a conspiracy to sell marijuana and cocaine, as
    opposed to solely cocaine).         Nor could she, since, as discussed in
    Part 
    I, supra
    , the vast majority of the evidence presented at
    trial--including evidence of all four types of drugs--related to
    the organization's activities at Victor Berríos.                Absent any
    showing of prejudice, we are unable to assign plain error to the
    alleged variance.
    -46-
    C.      Prejudicial Evidence
    Sonia next argues that the district court erred by
    admitting testimony that should have been excluded under Federal
    Rule of Evidence 403.              That rule provides:     "The court may exclude
    relevant     evidence         if    its   probative    value      is   substantially
    outweighed by a danger of . . . unfair prejudice, confusing the
    issues,    misleading         the     jury,   undue   delay,      wasting   time,    or
    needlessly presenting cumulative evidence."                    Fed. R. Evid. 403.
    Since her trial counsel failed to raise an objection to any of the
    testimony she now claims was wrongfully admitted under this Rule,
    she must show that the district court's failure to exclude such
    evidence amounted to plain error.                See 
    Rodriguez, 525 F.3d at 98
    (assessing newly-unveiled Rule 403 claim for plain error).                      This
    she cannot do.
    1.        Delgado's Shooting
    On direct examination, Delgado began testifying about a
    shooting he attempted to carry out against another co-conspirator
    when Delgado was still working for the Nazario brothers.                            The
    district court interrupted the testimony and then stated in open
    court    that     it    saw   "no    relationship     to   this    case."    Counsel
    requested no mistrial, nor was this remotely cause for a mistrial.
    In short, there was no error, much less plain error.
    -47-
    2.   Ramos's Threat to "Spill Blood"
    Andy testified about a threat Ramos made to "spill" the
    blood of a competitor at a drug point in Aguas Buenas if the
    competitor did not cease selling drugs there.20   Sonia makes a one-
    sentence argument that this testimony "was clearly more prejudicial
    than relevant, and unfairly distracted the jury from whether
    Appellant agreed to join a conspiracy with Ramos' enterprises in
    Caguas and Aguas Buenas, to how dangerous its members were."     She
    therefore appears to premise her argument on her belief that the
    organization's activities outside of Yabucoa constituted a separate
    conspiracy, and were thus irrelevant to her.       That premise is
    faulty, since, as we explained in addressing her prejudicial
    variance argument, the trial testimony from Andy showed evidence of
    interdependence   and   a   common    supply   chain   between   the
    organization's various drug points.    Ramos's attempts to maintain
    control over his drug points, rather than being a distraction, were
    certainly relevant to proving the conspiracy's existence. The fact
    that Sonia did not directly participate in this event does not--
    taken alone--deem the evidence unduly prejudicial with respect to
    20
    Ramos's counsel objected to this testimony, but Sonia's did
    not join in the objection.      We decline to deem the argument
    preserved for Sonia, particularly because the evidence pertained to
    Ramos, and the district court did not have an opportunity to
    evaluate its admissibility with regard to Sonia. Her argument is
    therefore forfeited and reviewed only for plain error. See United
    States v. Acosta-Colón, 
    741 F.3d 179
    , 189 (1st Cir. 2013)
    (rejecting an undeveloped argument that co-defendants may
    "piggyback" on one another's objections).
    -48-
    her conviction.             Cf. 
    Maryea, 704 F.3d at 73
    (explaining, in
    responding        to    a   prejudicial     variance    argument,   that    while
    "knowledge of the broader conspiracy's existence is critical," the
    "government need not prove that the defendant had knowledge of
    every other participant, or of the details of the conspiracy").
    Further, any potential prejudice against Sonia was diminished by
    the fact that Ramos never carried out the threat, and the incident
    did not involve her.
    3.        Shootout Between Sandra and Diana Flores-Rivera
    We have already described Andy's testimony related to
    Sandra and Diana's domestic dispute.              Sonia also challenges this
    evidence, but on Rule 403 rather Rule 404(b) grounds. Her claim of
    undue prejudice with respect to the domestic dispute evidence is
    even weaker than Sandra's 404(b) argument, because Sonia was not
    involved in the alleged shooting at all.               Sonia attempts to bridge
    this gap by claiming the story constituted evidence of guilt by
    association that "served to suggest that because [Sonia] was a
    member of this family, she must also be guilty."                 But given the
    evidence's        obvious      probative     value      in   illustrating     the
    organization's disciplinary system, in addition to her failure to
    object below, this is a bridge too far.
    Having rejected each of her Rule 403-based arguments, we
    proceed to Sonia's next category of claimed evidentiary errors.
    -49-
    D.   Testimony Based on "Speculation"
    On     direct    examination,      Xiomara   testified   that     the
    notation    "M.I."     in    one   of   the    drug   ledgers   written   by   co-
    conspirator Sandra Fernandez-Espinosa21 could have referred to
    either     "Mimi"    (Sonia's      nickname)     or   another   co-conspirator,
    "Miguelito."         Sonia claims on appeal that this testimony was
    admitted in violation of Federal Rule of Evidence 602 because
    Xiomara lacked sufficient personal knowledge to connect the ledger
    notation to Sonia.          Rule 602 provides: "A witness may testify to a
    matter only if evidence is introduced sufficient to support a
    finding that the witness has personal knowledge of the matter.
    Evidence to prove personal knowledge may consist of the witness's
    own testimony."
    We have previously stated that under Rule 602, testimony
    is inadmissible "only if in the proper exercise of the trial
    court's discretion it finds that the witness could not have
    actually perceived or observed what he testified to."                     United
    States v. Brown, 
    669 F.3d 10
    , 22 (1st Cir. 2012).                     "Personal
    knowledge can include inferences and opinions, so long as they are
    grounded in personal observations and experiences."               United States
    v. Rodriguez, 
    162 F.3d 135
    , 144 (1st Cir. 1998) (internal quotation
    marks omitted).
    21
    The ledgers were seized by the agents and had previously
    been admitted into evidence without objection.
    -50-
    As a threshold matter, Sonia and the government dispute
    whether Sonia's trial counsel made a contemporaneous objection to
    this testimony at trial.            We need not definitively decide whether
    her claim of error is preserved because, even under the less
    deferential standard of review for preserved claims of error, Sonia
    fails    to    show    that     the    admission      of     the    ledger     testimony
    constituted reversible error.
    Simply put, the jury was entitled to hear Xiomara's
    testimony and afford it the proper amount of weight.                            Xiomara
    testified that she personally tallied the drugs with Fernandez-
    Espinosa, and that she watched Fernandez-Espinosa make recordings
    in the ledger.         Given Xiomara's role in the conspiracy, and her
    testimony that Sonia acted as a runner, Xiomara could have fairly
    inferred      that    the   notation     referred       to    one   of   the    two   co-
    conspirators she named. See 
    Rodriguez, 162 F.3d at 144
    . Moreover,
    considering Xiomara, Delgado, and Andy's other testimony about
    Sonia's involvement, any error caused by the introduction of the
    evidence was harmless. See United States v. Muñoz-Franco, 
    487 F.3d 25
    , 63 (1st Cir. 2007) (internal quotation marks omitted).
    Sonia    makes    a     similar    Rule   602    argument,       this   one
    indisputably raised for the first time on appeal, about Xiomara's
    testimony that she saw Sonia carrying bags containing drugs while
    acting as a runner for the organization.                We find no plain error in
    the     district      court's    decision        to   admit     this     unobjected-to
    -51-
    testimony.        Xiomara's belief that the bags contained drugs were
    based on what "everybody knew."            Absent an objection, the district
    court lacked an opportunity to determine whether Xiomara meant that
    co-conspirators had told her what was in the bags, in which case
    the evidence may have been admissible under the co-conspirator
    hearsay exception, see Fed. R. Evid. 801(d)(2)(E),22 or whether her
    statement was based on unsupported speculation.                  We thus decline
    the invitation to disturb the district court's judgment based on
    the cold appellate record.           Cf. United States v. Houlihan, 
    92 F.3d 1271
    , 1297 (1st Cir. 1996).
    Finally, Sonia makes a two-sentence argument that Delgado
    lacked        personal   knowledge    to   testify   that   Sonia    stored   the
    organization's drug trafficking proceeds.               She claims that the
    testimony was based on inadmissible hearsay--statements by co-
    conspirator        Zavala-Martí–-but       her   argument   is    based   upon   a
    misreading of the trial transcript.              When asked how he knew that
    the drug money was given to Sonia, Delgado testified that he "saw
    her."        There was no contemporaneous objection to this testimony at
    trial.        Of course, personally viewing Sonia procure the money was
    22
    Rule 801(d)(2)(E) provides that a statement offered against
    a party that is made by that party's co-conspirator during and in
    furtherance of the conspiracy is not hearsay.
    -52-
    a sufficient basis for Delgado to conclude that Sonia served in
    that role.23
    E.   Jury Instructions
    Sonia claims in a parenthetical of her opening brief that
    the district court's failure to instruct the jury "that it must
    determine the guilt of each defendant on each count separately"
    amounted to a "distinct and serious plain error."     There was no
    objection to this instruction at trial.   We decline to construct
    Sonia's arguments for her, and we thus deem this assignment of
    error waived.   See United States v. Sevilla-Oyola, 
    770 F.3d 1
    ,
    13—14 (1st Cir. 2014) (explaining that "[a]rguments raised in only
    a perfunctory and undeveloped manner are deemed waived on appeal").
    23
    After Delgado stated how he knew Sonia stored the funds,
    he was asked by the prosecutor how he knew "where the money ended
    up after leaving [Sonia's] hands." Ramos's trial counsel lodged an
    objection at this point ("Objection, if he doesn't know"), but
    Sonia's did not. Delgado then explained the basis for his personal
    knowledge: Zavala-Martí, an undisputed leader of the organization,
    told Delgado that Diana Flores-Rivera picked up the money from
    Sonia and delivered it to Zavala-Martí. Zavala-Martí's statements
    themselves--made by a conspirator for the purpose of informing
    another conspirator what happened to the money--may have been
    admissible under the co-conspirator hearsay exception. See Fed. R.
    Evid. 801(d)(2)(E).      The application of the co-conspirator
    exception is complicated by Delgado's testimony that Zavala-Martí
    told him this information because, in Delgado's words, "I worked
    with the organization and we told each other, I mean, like as
    friends."   So, arguably, Zavala-Martí did not tell Delgado the
    information "in furtherance" of the conspiracy itself, as would be
    required by that exception. In any event, there was no objection
    to Zavala-Martí's second-hand remarks, and we find no plain error
    in the district court allowing the jury to find out what happened
    to the money after Sonia took it.
    -53-
    F.   Read-backs in the Jury Room
    During its deliberation, the jury sent a note to the
    trial judge that read, in relevant part: "We would like to hear the
    transcripts    from    Harry's   and   Xiomara's   testimony     that   make
    reference to Sonia Flores (Mimi)."        The judge, while in chambers
    with the prosecutor, defense counsel, and the court reporter,
    instructed the court reporter to read both the direct and cross-
    examination for those two witnesses.       The judge also explained the
    restricted nature of the read-back procedure:        "You are there as a
    stone," the judge told the court reporter.           The court reporter
    could read the transcripts, and repeat anything the jury requested
    to be repeated.       However, the jury was not permitted to ask the
    court reporter any other questions, nor was it allowed to make any
    comments in the court reporter's presence.
    The judge then asked the attorneys, "Do you want me to
    bring them out in court?"        Ramos and Sonia's attorneys responded
    that "we prefer in open court."         So the judge summoned the jury
    into the courtroom, reiterated the instructions and the limited
    nature of the read-back procedure, and confirmed that the jurors
    understood    the   applicable   restrictions.     The   jury    foreperson
    expressed a preference to do the read-back in the jury room, which
    the judge said was "[f]ine.        That's your choice."         None of the
    attorneys objected.
    -54-
    On appeal, Sonia claims that the court reporter's read-
    backs in the jury room violated her rights to a public trial, to be
    present for all parts of the trial, and to the assistance of
    counsel.     She also claims that the read-back procedure violated
    Federal Rule of Criminal Procedure 43 (the "Court Reporter's Act"),
    which requires the defendant to be present "at every trial stage."
    We note at the outset that the trial transcript does not
    evince any contemporaneous objection to the district court's grant
    of permission for the jury to retire to the jury room during the
    read-backs.    This finding disposes of Sonia's Rule 43 claim, as we
    have refused to entertain similar Rule 43 arguments on appeal where
    trial counsel had a clear opportunity to object, but did not.            See
    United States v. Fernández-Hernández, 
    652 F.3d 56
    , 66 (1st Cir.
    2011) ("[E]ven assuming [the defendant] had a statutory right to be
    present under Rule 43 in these circumstances[,] . . . he waived
    that right by remaining silent.") (citing United States v. Gagnon,
    
    470 U.S. 522
    , 529 (1985)).
    As for her constitutional claims, we find no plain error
    in the way the district court handled the read-backs. We rest this
    finding primarily on the second prong of the plain error test
    (requiring    the   error   to   be   "clear   and   obvious"),   see   Rios-
    Hernández, 
    645 F.3d 456
    , 462—63 (1st Cir. 2011), because our
    circuit has yet to establish any bright-line rules on read-back
    procedures.    For example, in United States v. Luciano-Mosquera, 63
    -55-
    F.3d 1142, 1156—57 (1st Cir. 1995), we addressed a situation where
    a trial judge sent a court reporter to conduct a read-back in the
    jury room without doling out any cautionary instructions.     Since
    defense counsel did not object, and since "[t]here [was] no
    evidence that anything untoward happened in the jury room and no
    reason to think the reporter did anything other than properly read
    the pertinent portions of the record," we declined to reverse the
    defendant's convictions.   
    Id. at 1157.
       Here, the district court
    provided explicit cautionary instructions in open court, and from
    our reading of the record, defense counsel appeared to accede to
    the procedure as it unfolded.         While it may well have been
    preferable for the district court, in an abundance of caution, to
    conduct the read-backs in the presence of the defendants and their
    attorneys, we find no plain error in its decision.
    G.   Delgado's Testimony About Meeting Ramos in Bayamón 308
    Prior to trial, the government disclosed to the court and
    the defendants that it could not verify from the available prison
    records that Delgado and Ramos were simultaneously incarcerated at
    the "Bayamón 308" prison in 1998, even though Delgado told the
    grand jury that the two first met there that year.   The government
    then informed the court and the defendants that it would not be
    -56-
    presenting any evidence about their alleged meeting on direct
    examination.24
    Nevertheless, on Delgado's cross-examination, Ramos's
    counsel chose to elicit Delgado's story about meeting Ramos at
    Bayamón 308 in an apparent attempt to impeach Delgado by reference
    to the earlier grand jury testimony.   Delgado then claimed that he
    spoke to someone claiming to be named "Robert Belleza" (Ramos's
    alias) through windows and pipes at Bayamón 308, although he denied
    ever seeing Ramos there face-to-face.    There was no objection by
    the defense, which intended to bring out the testimony all along.25
    When it came time for the defense to present its own evidence,
    Ramos's counsel introduced a prison administrator to testify as to
    the prison records' failure to show any overlap between Ramos and
    Delgado's incarceration at Bayamón 308 in 1998, although the
    records did show that both were imprisoned there close in time to
    one another.     On cross-examination of the administrator, the
    prosecutor tried to show that the records were unreliable.
    24
    This exchange is not in the record, but it is referred to
    in the trial transcript.
    25
    Omar's counsel stated during his opening statement that
    "[Delgado] told the grand jury that he met [Ramos] while he was in
    prison in 1998." At that point, the prosecutor requested a sidebar
    to express her concern that Omar's counsel was inviting a mistrial
    by telling the jury that Ramos had previously been incarcerated.
    The district court replied that it was "sure that counsel has
    gotten all ready for this trial," and declined to take any further
    action. Omar's counsel proceeded with his opening, stating that
    Delgado lied to the grand jury about meeting Ramos at Bayamón 308.
    -57-
    The next day, Sonia's counsel filed a written "Motion to
    Order the Government to Fulfill its Obligation Under Napue."            Her
    motion argued that by failing to correct Delgado's testimony about
    Bayamón 308, the prosecution had "knowingly use[d] false . . .
    testimony" in violation of Napue v. Illinois, 
    360 U.S. 264
    , 269
    (1959).    Counsel orally raised the motion the next day, and
    requested a mistrial, which the district court denied.             We thus
    treat her Napue argument as properly preserved for appeal, and our
    review of the district court's denial to retry the case is for
    manifest abuse of discretion.      See 
    González-González, 258 F.3d at 22
    .
    Under Napue, a prosecutor "may not knowingly use false
    evidence, including false testimony, to obtain a tainted conviction
    regardless of whether the prosecutor solicits false evidence or
    . . . allows false evidence to go uncorrected when it appears."
    United States v. Mangual-Garcia, 
    505 F.3d 1
    , 10 (1st Cir. 2007)
    (quoting 
    Napue, 360 U.S. at 269
    ) (internal quotation marks and
    alterations omitted).     However, "[w]hen the defendant knows about
    the false testimony and fails to bring it to the jury or the
    court's attention, the assumption is that he did so for strategic
    reasons, and the defendant will not be able to question his own
    strategic choices on appeal."      
    Id. at 10—11.
    We   reject   Sonia's   Napue   argument   for   two   principal
    reasons.
    -58-
    First, it is a stretch to say that Delgado's testimony
    about meeting Ramos at Bayamón was "knowingly . . . false" to the
    prosecutor.      Delgado testified that he spoke through windows and
    pipes to someone who called himself by Ramos's alias, and that he
    thought the person was Ramos, but that he did not see the speaker's
    face.    The prosecutor's decision not to elicit the testimony at
    trial was based on her discovery that the story was uncorroborated
    by available prison records.       That lands short of an admission by
    the prosecutor that she knew Delgado was lying.                  Under these
    circumstances--especially        where     the     prosecutor   brought      the
    inconsistency to the attention of the court and defense counsel
    prior to trial--the prosecutor's decision not to "correct" the
    testimony when it was thereafter elicited by the defense was not
    improper.
    Second, the testimony only came before the jury for the
    defense's own "strategic reasons." 
    Mangual-Garcia, 505 F.3d at 10
    .
    Just    as   a   defendant's   strategic    failure    to   object    to   false
    testimony will not create a Napue                violation, neither will a
    defendant's strategic elicitation of such testimony.                 Cf. 
    id. at 10—11
    & n.7 (collecting cases for the proposition that the tactical
    omission of an objection does not give rise to a Napue claim).
    This is especially true when, as here, defense counsel came
    prepared to impeach said testimony.
    -59-
    H.   Sentencing Challenges
    Sonia makes what we interpret to be two categories of
    challenges relating to her 151-month sentence.
    1.   Firearm Enhancement
    Despite the prosecutor's decision to dismiss the firearms
    count against Sonia, the district court imposed a two-level firearm
    enhancement under U.S.S.G. § 2D1.1(b)(1), which contributed to
    Sonia's total offense level of 34.26   Sonia levied an objection to
    the enhancement in her sentencing memorandum, renewed the objection
    at her sentencing hearing, and assigns error to the enhancement's
    application once again on appeal.    Arguments such as Sonia's--that
    the district court wrongly applied the facts of the case in
    imposing a guidelines enhancement--are subject to clear error
    review.   See United States v. Thongsophaporn, 
    503 F.3d 51
    , 57—58
    (1st Cir. 2007).27
    Section    2D1.1(b)(1)'s   firearm    enhancement        "applies
    whenever a codefendant's possession of a firearm in furtherance of
    their joint criminal venture [is] reasonably foreseeable" by the
    26
    Sonia's 151-month sentence sat         at   the   bottom    of   the
    guidelines range for that offense level.
    27
    The heading to this section of Sonia's brief states that her
    sentence was procedurally and substantively unreasonable, but she
    makes no argument to this effect. We therefore deem any challenge
    to her sentence's procedural and substantive reasonableness waived,
    aside from her argument regarding the firearm enhancement. See
    United States v. Rossignol, 
    780 F.3d 475
    , 477 & n.2 (1st Cir.
    2015).
    -60-
    defendant.     United States v. Bianco, 
    922 F.2d 910
    , 912 (1st Cir.
    1991).28    Even though there was no direct evidence at trial or in
    the presentence investigation report evidencing Sonia's awareness
    of the use of firearms in connection with the conspiracy, our
    circuit's case law on point piles a mountain too high for her to
    climb.     Indeed, "[b]ecause firearms are considered common tools of
    the drug trade," where firearms are used in furtherance of drug
    offenses, the two-level "enhancement should be applied if [a]
    weapon was present, unless it is clearly improbable that the weapon
    was connected with the offense."         
    Thongsophaporn, 503 F.3d at 58
    (internal quotation marks omitted).
    Here, the trial testimony showed that Sonia was a runner
    of crack, cocaine, and marijuana, and that she helped stash all
    four types of drugs sold by the organization. She had contact with
    several     other   co-conspirators,   including   Delgado,   who   had   a
    reputation for shooting his gun.29       Finding, as we do, that the use
    of firearms during and in furtherance of the conspiracy was not
    "clearly improbable" from Sonia's perspective, we see no clear
    error in the district court's choice to apply the enhancement.
    28
    U.S.S.G. § 1B1.3(a)(1)(B) requires the sentencing court to
    consider "in the case of a jointly undertaken criminal
    activity . . ., all reasonably foreseeable acts and omissions of
    others in furtherance of the jointly undertaken criminal activity."
    29
    Delgado had a reputation for donning a bulletproof vest and
    frequently firing guns while at the housing project. He testified
    that he was armed "all the time."
    -61-
    2.     Fair Sentencing Act Amendments
    Sonia next argues that she is entitled to resentencing
    under the Fair Sentencing Act of 2010 ("FSA"), which was passed
    five months after the district court imposed her sentence.                         Our
    circuit      has    already    decided      that    the   FSA    does    not   apply
    retroactively to those who, like Sonia, were sentenced before the
    FSA's enactment.        See United States           v. Goncalves, 
    642 F.3d 245
    ,
    253—54 (1st Cir.), cert. denied, 
    132 S. Ct. 596
    (2011).                            Her
    argument thus necessarily fails.30
    Anticipating our disagreement with her retroactivity
    argument, Sonia asks us to "address the issue raised here to guide
    the District Court in the exercise of its discretion pursuant to 18
    U.S.C. § 3582(c)(2)."           Section 3582(c)(2) provides that "in the
    case    of    a    defendant    who   has    been    sentenced    to    a   term    of
    imprisonment based on a sentencing range that has subsequently been
    lowered by the Sentencing Commission . . ., the court may reduce
    the term of imprisonment."            (Emphasis supplied).        The statute, by
    its plain language, is triggered in the first instance by the
    discretion of the sentencing judge, not the Court of Appeals.
    Sonia does not point to any evidence that she brought this request
    to   the     district   court    in   the    intervening    years       between    the
    30
    Sonia also seems to argue that the imposition of her pre-FSA
    sentence violated the Equal Protection and Due Process clauses of
    the constitution.    We deem her glancing references to those
    constitutional provisions as waiving any viable challenge to her
    sentence for which they form a basis.
    -62-
    imposition of her sentence and this appeal.   Therefore, we reject
    Sonia's invocation of section 3582(c), without opining on her
    eligibility for a sentence reduction.
    VI.   Conclusion
    To summarize, appellants Carlos Omar Bermúdez-Torres and
    Cruz Roberto Ramos-González are entitled to a new trial on all six
    counts of their conviction, plus the forfeiture count.   We remand
    their cases to the district court for a new trial. Having rejected
    each of Sandra and Sonia Flores-Rivera's challenges, we affirm
    their respective convictions and sentences.
    So ordered.
    -63-