Full opinion text
TORRUELLA, Circuit Judge. Appellants were convicted of conspiracy to possess with intent to distribute approximately 1400 grams of heroin and 9445 kilograms of cocaine, in violation of 21 U.S.C. §§ 841(a)(1) and 846. They now challenge their convictions and their sentences. We affirm their convictions but vacate their sentences and remand for re-sentencing. I. Background On March 21, 1994, Special Agents Jay Stoothoff (“Agent Stoothoff’) of the Drug Enforcement Administration (“DEA”) and Richard Escalera of the Immigration and Naturalization Service were conducting surveillance at the Luis Muñoz Marín International Airport in Carolina, Puerto Rico. They saw two vehicles, a Pontiac TransAm carrying four people and an Isuzu Trooper carrying two people, pull up to the departure area together. After observing suspicious interactions between certain passengers of the vehicles and American Airlines employees, the agents approached the vehicles and identified themselves as police officers. One of the individuals fled on foot, while two individuals sped away in the TransAm. The Trooper was left with the doors open and engine running, and the agents detained the other three individuals. The agents secured four suitcases from the scene. These suitcases were found to contain eighty-one kilograms of cocaine. One of the detained individuals, Héctor Martinez-Medina (“Martinez-Medina”), accompanied the agents to a house where all six individuals met prior to going to the airport. The house belonged to the father of Israel Pérez-Delgado (“Pérez”). The Isuzu Trooper was registered to Pérez. This series of events eventually led to the exposure of the drug conspiracy that gave rise to this case. On August 8, 1996, the grand jury returned a six-count superseding indictment against sixty defendants, including appellants. Count One of the indictment charged all the defendants with conspiracy to possess with intent to distribute approximately 1400 grams of heroin and 9445 kilograms of cocaine, in violation of 21 U.S.C. §§ 841(a)(1), 846. Count Two charged appellant Angel Luis Pizarro (“Pizarro”) and various co-defendants not part of this appeal with possession with intent to distribute approximately eighty-one kilograms of cocaine, in violation of 21 U.S.C. § 841(a)(1) and 18 U.S.C. § 2. Count Three did not charge any of the appellants. Count Four charged appellants John Correy (“Correy”) and Raymond Ni-colai-Cabassa (“Nicolai”), as well as co-defendant Thomas Martínez (“Martinez”), who is not part of this appeal, with possession with intent to distribute approximately thirty-six kilograms of cocaine, in violation of 21 U.S.C. § 841(a)(1) and 18 U.S.C. § 2. Counts Five and Six charged Correy and Nicolai with the intentional killings of José Miguel Blanco-Rodríguez (“Blanco”) and Ramón de Jesús-Molina (“de Jesús”). United States District Judge Carmen Consuelo Vargas de Cerezo presided over a jury trial for ten of the co-defendants, including appellants, in the United States District Court for the District of Puerto Rico. Trial began on May 12, 1999 and lasted approximately seven months. The jury convicted all of the appellants of Count One, convicted Pizarro of Count Two, acquitted Correy of Count Four, and acquitted Correy and Nicolai of Counts Five and Six. On April 17, 2002, pursuant to an order of the First Circuit Judicial Council, the case was reassigned to the Honorable Héctor M. Laffitte for sentencing. Judge Laf-fitte sentenced the appellants on various dates between May 7, 2002 and July 18, 2002. Appellants have timely appealed both their convictions and their sentences to this court. II. Discussion Appellants challenge their convictions and sentences on numerous grounds. We address each of these grounds in turn. A. Conviction 1. Delay Appellants Correy, Pizarra, and Nicolai argue that their convictions should be reversed and the indictments against them dismissed because the delay between their indictment and trial violated their rights under the Speedy Trial Act (“STA”), 18 U.S.C. § 3161, and the Sixth Amendment of the Constitution. Appellants were originally indicted on December 13, 1995, and a superseding indictment was filed on August 8,1996. Trial commenced on May 12, 1999, approximately forty-one months after appellants were indicted. a. Speedy Trial Act We review decisions on issues of fact relevant to the STA for clear error and review questions of law de novo. United States v. Maxwell, 351 F.3d 35, 37 (1st Cir.2003). The STA requires that trial commence within seventy days of the filing of an indictment, or the first appearance of the defendant in court, whichever is later. 18 U.S.C. § 3161(c)(1). Periods of delay arising from the causes outlined at 18 U.S.C. § 3161(h)(l)-(9) are excluded from the calculation. Included in these periods of delay are those “resulting from any pretrial motion, from the filing of the motion through the conclusion of the hearing on, or other prompt disposition of, such motion.” Id. § 3161(h)(1)(F). If trial does not commence by the end of seventy days plus the excluded periods, the “indictment shall be dismissed on motion of the defendant.” Id. § 3162(a)(2). Nicolai moved to dismiss on the basis of an STA violation on March 3, 1998, and Pizarra claims to have joined the motion. Correy filed a pro se motion to dismiss for delay on July 22, 1998 and moved to dismiss for lack of prosecution and violation of the Sixth Amendment on April 30, 1999. Although Correy’s motions never mentioned the STA by name, we will assume, as did the prosecution and district court, that his motions were sufficient for purposes of § 3162(a)(2). Our review of the district court’s refusal to dismiss the indictment turns on whether delays resulting from the pendency of motions filed by appellants and their co-defendants are excluded from the seventy-day limit. Appellants each claim that the STA clock began running on their respective dates of first appearance, and that the seventy-day deadline was far exceeded. However, among the periods excluded from the STA limit are “reasonable period[s] of delay when the defendant is joined for trial with a codefendant as to whom the time for trial has not run and no motion for severance has been granted.” Id. § 3161(h)(7). The Supreme Court has interpreted this section to mean that the clock does not, in effect, begin to run until the' date of the most recent defendant’s initial appearance before the court. See Henderson v. United States, 476 U.S. 321, 323 n. 2, 106 S.Ct. 1871, 90 L.Ed.2d 299 (1986) (finding that STA clock begins on the date of last co-defendant’s arraignment because “[a]ll defendants who are joined for trial generally fall within the speedy trial computation of the latest codefen-dant”) (citing 18 U.S.C. § 3161(h)(7)); United States v. Barnes, 251 F.3d 251, 257-59 (1st Cir.2001) (applying Henderson to find that district cburt properly reset STA clock on date superseding indictment was filed to add a new defendant); see also United States v. Maxwell, 351 F.3d 35, 38 (1st Cir.2003) (applying Barnes to find that period between appellant’s arraignment and co-defendant’s later arraignment is excluded from STA calculation). Appellants were among ten defendants severed for trial from the remaining fifty' who were charged in the superseding indictment. The last of these ten to appear before the court was Nicolai, on November 6, 1996. Accordingly, the STA clock started no earlier than that date, 917 days before trial. Our precedent makes clear that “any defendant’s motion resulting in ex-cludable time toll[s] the STA clock for his codefendants.” United States v. Santiago-Becerril, 130 F.3d 11, 19 (1st Cir.1997) (collecting cases). Accordingly, the government argues that delays during the pendency of motions filed by appellants’ co-defendants must be excluded from the STA calculation. See 18 U.S.C. § 3161(h)(1)(F), (h)(7). The government argues that once the delays during the pendency of motions filed by appellants’ co-defendants are counted, fewer than seventy non-excludable days accrued. Unfortunately, the government neglected to provide this court with the dates or length of any delays so occasioned during the more than two-year interval between Nicolai’s initial appearance and trial. This case began with sixty co-defendants, a number that was cut down to ten by the time of trial. The co-defendants filed numerous motions, and there were also many hearings and appearances before the district court prior to trial. After carefully examining the record, we have concluded that such motions and proceedings tolled the STA for the bulk of the time between Nicolai’s initial appearance and trial. The number of non-excludable days for STA purposes, due to the various motions and hearings, was far less than seventy. Appellants Pizarro and Nicolai argue that the exclusion of delays during the pendency of a co-defendant’s motion must be reasonable, see 18 U.S.C. § 3161(h)(7), and therefore other considerations — such as whether the defendant seeking dismissal asserted his speedy trial rights or contributed to the delay — play a role in calculating the number of excludable days. Defendants rely on Barnes. See 251 F.3d at 259 (finding no STA violation but noting that “[t]he Henderson rule anticipates exceptions” and that “in other, less exigent circumstances, the clock may not prove to be so elastic”). According to appellants, because they did not contribute to their delay and because they asserted their speedy trial rights, their STA clocks should be considered separately from the clocks of their co-defendants. Appellants have not arg-ued that the joining of various co-defendants for trial was unreasonable for STA purposes. Appellants’ reliance on Barnes is misplaced, and their claims that they were not responsible for any delays are inaccurate. Barnes involved the re-trial of a defendant after this court vacated her original conviction and ordered her indictment dismissed without prejudice because the government had violated the STA. See id. at 254. A grand jury promptly issued a second indictment. One day before the defendant-appellant’s STA deadline, a grand jury issued a superseding indictment that added a second defendant. This court found no STA violation but expressed concern because the government, “after once violating the appellant’s STA rights, ... filed the superseding indictment only one day before the STA clock was to expire again.” Id. at 259 (emphasis in original). In other words, the Barnes court was concerned with the appearance of possible manipulation of the STA by the government. In the instant case, however, the causes of delay were the numerous motions filed by the co-defendants, including appellants Pizarro and Nicolai, who between them filed at least thirty-six motions from November 6, 1996 through May 12, 1999, the date trial began. Further, Barnes involved the joining of a co-defendant, not the filing of pretrial motions, and therefore concerned § 3161(h)(7), not § 3161(h)(1)(F). The Supreme Court has interpreted § 3161(h)(1)(F) not to have any “reasonableness” requirement such as the one present in § 3161(h)(7). See Henderson, 476 U.S. at 326-28, 106 S.Ct. 1871; Maxwell, 351 F.3d at 38. Therefore, appellants’ argument that delays caused by pretrial motions filed by their co-defendants were unreasonable finds no support in Barnes and has been rejected by the Supreme Court in Henderson. Due to the pendency of motions filed by co-defendants, the number of nonexcluda-ble days for STA purposes between Nico-lai’s indictment and trial was less than seventy. Accordingly, no STA violation occurred. b. Sixth Amendment Although unusual, it is possible for a delay that does not violate the STA to run afoul of the Sixth Amendment’s guarantee of a speedy trial. United States v. Salimonu, 182 F.3d 63, 69 (1st Cir.1999); see also 18 U.S.C. § 3173 (STA not a bar to Sixth Amendment claim). Appellants allege that delays between their indictment and trial, and between their conviction and sentencing, violated the Sixth Amendment’s guarantee of “a speedy and public trial.” U.S. Const, amend. VI. In Barker v. Wingo, 407 U.S. 514, 92 S.Ct. 2182, 33 L.Ed.2d 101 (1972), the Supreme Court identified four factors to be considered in determining whether an appellant’s speedy trial rights have been violated: (1) the length of the delay, (2) the reasons for the delay, (3) the defendant’s assertion of his speedy trial right, and (4) prejudice to the defendant caused by the delay. Id. at 530-32. However, “none of the four factors ... [is] either a necessary or sufficient condition to the finding of a deprivation of the right of speedy trial. Rather, they are related factors and must be considered together with such other circumstances as may be relevant.” Id. at 533. The length of pretrial delay is calculated from either arrest or indictment, whichever occurs first. See United States v. Muñoz-Amado, 182 F.3d 57, 61 (1st Cir.1999). Correy and Pizarro were both indicted prior to their arrest, in December 1995. Nicolai was arrested on November 6, 1996, although he was already incarcerated in New York after having pled guilty to unrelated charges. Thus, all three waited over forty months for trial. This time period far exceeds the one-year point at which pretrial delay is generally considered to be presumptively prejudicial. See Santiago-Becerril, 130 F.3d at 21-22 (quoting Doggett v. United States, 505 U.S. 647, 652 n. 1, 112 S.Ct. 2686, 120 L.Ed.2d 520 (1992)). Accordingly, the length of delay weighs in favor of appellants’ claim of a Sixth Amendment violation. The second factor, however, weighs against appellants. They allege that the delay was caused largely by the unpreparedness of the government, ánd the inability of the judicial system to cope with their case. We disagree. Sixty people were indicted in this large, complex drug conspiracy case. Well over 350 pretrial motions were filed between the initial indictment and trial. Pizarro filed thirteen pretrial motions, including two motions to continue the trial (Docket No. 504, 531); two motions to change his plea (Docket Nos. 701, 916), each of which was withdrawn months later, shortly before the scheduled change of plea hearing (Docket Nos. 766, 974); and three motions for his court-appointed attorney to withdraw (Docket Nos. 635, 746, 974), resulting in additional delay while a new attorney was appointed. Correy filed nineteen pretrial motions, including one to continue the trial. (Docket No. 533). Nicolai filed twenty-eight pretrial motions, including two for a continuance or severance. (Docket No. 532,1040). Appellants have alleged no bad faith effort by the government to delay the proceedings. Nor do we agree with appellants’ assertion that the delay was caused by the judicial system’s inability to cope with a case this size. From our review of the record, the district court disposed of the co-defendants’ numerous motions in a timely manner and moved the case along to trial. Instead, it appears that delays were due in large part to the resolution of pre-trial matters concerning appellants and their co-defendants. Further, while a case of this size is certainly unwieldy, the joint prosecution of defendants involved in the same drug trafficking conspiracy is justified as a means of serving the efficient administration of justice. Accordingly, we find that the reasons for the delay are sound and weigh against a finding of Sixth Amendment violation. With regard to the third factor, the government concedes that all three appellants asserted their speedy trial rights in motions filed with the district court. We find, therefore, that the third factor weighs in appellants’ favor. We evaluate the fourth factor, prejudice, “in the light of the interests of defendants which the speedy trial right was designed to protect[:] ... (i) to prevent oppressive pretrial incarceration; (ii) to minimize anxiety and concern of the accused; and (iii) to limit the possibility that the defense will be impaired.” Barker, 407 U.S. at 532, 92 S.Ct. 2182. All three appellants were detained for more than forty-one months prior to trial and likely experienced the disadvantages thereof identified by the Supreme Court in Barker, such as idleness, loss of employment, and disruption of family relationships. Id. Lengthy detention is not necessarily, however, “□sufficient to establish a constitutional level of prejudice.” Santiago-Becerril, 130 F.3d at 23 (finding fifteen months’ pretrial detention insufficient to establish prejudice); see also Barker, 407 U.S. at 533-34, 92 S.Ct. 2182 (finding that “prejudice was minimal” despite “extraordinary” five-year delay because defendant was only held in pretrial detention for ten months). The fact that appellants’ detention was forty-one months (almost three times the length considered in Santiago-Becerril) causes us great concern. However, we believe that other counterbalancing factors outweigh this deficiency and prevent constitutional error. Appellants have not alleged that the conditions of their confinement were unduly oppressive, and the time served was credited against the sentences they received upon conviction. Cf. Barker, 407 U.S. at 533, 92 S.Ct. 2182 (stating that “[i]t is especially unfortunate to impose [the disadvantages of pretrial detention] on those persons who are ultimately found to be innocent”). Moreover, at least some of the delay during appellants’ pretrial detention was attributable to their own actions, insofar as the many motions they filed required consideration and disposition by the district court. Appellants also allege that they suffered prejudice in the form of “anxiety and concern,” id. at 532, about the outcome of the proceedings. However, “[w]hile this type of prejudice is not to be brushed off lightly, considerable anxiety normally attends the initiation and pendency of criminal charges; hence only undue pressures are considered.” United States v. Henson, 945 F.2d 430, 438 (1st Cir.1991) (internal quotation marks and citations omitted); see also United States v. Colombo, 852 F.2d 19, 25 (1st Cir.1988) (emphasizing that Barker requires minimization, not elimination, of “the natural consequences of an indictment”). Correy and Nicolai both claim that, because they were indicted on murder charges, they experienced heightened concern that they might have to defend themselves against a death sentence, and Correy claims that he was distracted thereby from preparing his defense on other charges. See 21 U.S.C. § 848(e) (providing for death penalty). The government, however, never filed notice that it would seek the death penalty. See 18 U.S.C. § 3593. Accordingly, we think that the potential anxiety arising from Correy and Nicolai’s indictment on a death-eligible charge was minimized and did not exert “undue pressure” upon them. Finally, Nicolai and Pizarro claim that their defense was impaired as a result of the delay between indictment and trial. The Supreme Court identified this as “the most serious [consequence of delay] ... because the inability of a defendant adequately to prepare his case skews the fairness of the entire system.” Barker, 407 U.S. at 532, 92 S.Ct. 2182. In particular, Nicolai notes that government agents’ debriefing notes of government witness José Vélez-Román (“Velez”) were unavailable because they had been destroyed by Hurricane George in 1998, and that he was unable to present Alexandra Brocksman as a defense witness because she became ill. We note that the issue of the missing notes came up at trial while Pizarro’s counsel, not Nicolai, was cross-examining a government witness. Nicolai does not appear to have ever sought access to the notes and has not explained how the destruction of the notes prejudiced him in any way. Regarding the availability of Alexandra Brocksman, Nicolai has not explained how the passage of time prevented him from calling Brocksman as a witness. We note also that, while Nicolai states in his brief that Brocksman did not appear because she was ill, he alleged below that Pérez had threatened Brocksman prior to her failure to appear as a defense witness. See United States v. Nicolai-Cabassa, No. 95-405 (D.P.R. Dec. 9, 1999) (order requiring transcript of Nicolai’s statement regarding alleged threats made by Pérez to Brocksman). Further, the parts of the record Nicolai cites in his brief do not even mention Brocksman at all. For these reasons, we are unable to see how these alleged instances were either tied to passage of time or prejudiced Nicolai in any way. Both Nicolai and Pizarro claim that the principal government witness, Pérez, blamed the passage of time for his inability to recall certain details of the drug conspiracy he ran. However, “the clouded recollection of a key prosecution witness would seem- to be helpful, rather than harmful, to the defense.” Rashad v. Walsh, 300 F.3d 27, 42-43 (1st Cir.2002); see also United States v. Casas, 356 F.3d 104, 113 (1st Cir.2004) (holding that diminished witness recall resulting from delay “ ‘is a two-edged sword ... [because] [i]t is the Government that bears the burden of proving its case beyond a reasonable doubt’ ”) (quoting United States v. Loud Hawk, 474 U.S. 302, 315, 106 S.Ct. 648, 88 L.Ed.2d 640 (1986)). Indeed, two of Pérez’s eight references to the time lapse identified by appellants are taken from cross-examinations that focused specifically on discrediting Pérez’s testimony on the basis of his inability to recall specific details. (TT 6/7/99: 84-89; TT 6/9/99: 51-53). We cannot conclude that appellants suffered any prejudice as a result of Pér-ez’s limited recollection. The forty-one months that passed between appellants’ initial indictment and trial constituted an unusually long wait, particularly for defendants held in pretrial detention. Nevertheless, under the circumstances, we find that the large and complex nature of the proceedings and the district court’s obligation to consider the multitude of pretrial matters filed by appellants and their co-defendants are compelling reasons for the lengthy delay, and that appellants did not suffer prejudice of a constitutional dimension as a result thereof. We conclude that there was no violation of the Sixth Amendment as a result of pretrial delay. Finally, Pizarro and Nicolai argue that the delay between their conviction and sentencing resulted in a denial of their Sixth Amendment rights. They were sentenced on July 11 and July 31, 2002, respectively, approximately thirty-one months after their December 14, 1999 convictions. While “[t]he Supreme Court has not definitively held that [the right to a speedy trial] extends to the sentencing phase,” United States v. Nelson-Rodriguez, 319 F.3d 12, 60 (1st Cir.2003) (citing Pollard v. United States, 352 U.S. 354, 361, 77 S.Ct. 481, 1 L.Ed.2d 393 (1957)), we will assume, without deciding, that it does. See id.; see also Fed.R.Crim.P. 32(b)(1) (sentence must be imposed “without unnecessary delay”). While the delay between conviction and sentence was, again, unusually long in this case, it was not without good reason. It was necessary for transcripts of the seven-month trial to be prepared and reviewed in order to produce pre-sentence reports (PSRs) for the defendants. In addition, a number of post-trial motions were filed by appellants and their co-defendants. Nicolai filed twenty-two motions following his conviction, at least three of which requested continuances or extensions of time. Pizarro filed seventeen motions, requesting seven continuances or extensions of time. Neither appellant claims to have asserted a constitutional right to a speedy sentence. Nor do they explain what prejudice resulted from the delay, except to suggest that they were prejudiced by having to wait to file the instant appeal. We are not convinced that they were prejudiced, especially since some of the sentencing delay was to give defendants the opportunity to file Rule 29 motions for acquittal and motions for a new trial, which might have mooted the appeal had they been successful. Thus, we find that the delay between appellants’ conviction and sentencing caused no violation of their rights under the Sixth Amendment. c. Motion to sever Nicolai filed two motions for severance (Docket Nos. 532, 1040), one of which was noted but never ruled on (Docket No. 540), while the other was denied without prejudice pending refiling on December 29, 1998. (Docket No. 1074). The renewed motion was again denied on March 12, 1999 for failure to comply with the order providing an opportunity to amend the earlier motion. Nicolai claims that the district court erred in denying his motions for severance. We review the denial of a motion to sever for abuse of discretion. United States v. Soto-Beniquez, 356 F.3d 1, 29 (1st Cir.2004). To demonstrate abuse of discretion, defendants must show that joinder deprived them of a fair trial, resulting in a miscarriage of justice. Because the general rule is that those indicted together are tried together to prevent inconsistent verdicts and to conserve judicial and prosecutorial resources, severance is particularly difficult to obtain where, as here, multiple defendants share a single indictment. Id. (internal citations omitted). See generally Zafiro v. United States, 506 U.S. 534, 537, 113 S.Ct. 933, 122 L.Ed.2d 317 (1993) (noting “a preference in the federal system for joint trials of defendants who are indicted together”). Nicolai claims to have been prejudiced by delay that resulted from being tried jointly with multiple co-defendants and points to the faster resolution of the trials of other co-defendants who were severed before trial. Regardless of whether Nicolai’s trial might have been speedier had it been severed, the delays did not cause significant prejudice, nor did they result in the denial of a fair trial or a miscarriage of justice. See United States v. LiCausi 167 F.3d 36, 48-49 (1st Cir.1999) (determining that appellant must show “ ‘prejudice greater than that which necessarily inheres whenever multiple defendants ... are jointly tried’ ”) (quoting United States v. Walker, 706 F.2d 28, 30 (1st Cir.1983)). We therefore find no abuse of discretion in the district court’s denial of Nicolai’s motions to sever. 2. Grand jury proceedings Casas and Bonilla-Lugo (“Bonilla”) seek dismissal of the indictment, arguing that the prosecutor engaged in misconduct be- fore the grand jury by failing to disclose the existence of alleged secret agreements with Pérez and Martinez for immunity for the Blanco and de Jesús murders, and by knowingly presenting false testimony. Ca-sas argues that the false testimony came in the form of conflicting accounts of the murders from Pérez and Martinez, while Bonilla bases his argument on statements Martinez made at trial that were not made in his grand jury testimony. Casas also outlines each overt act in which he was implicated, challenging the sufficiency of the evidence to support his participation. The petit jury’s finding beyond a reasonable doubt that appellants were guilty of the charges alleged in the indictment “demonstrates a fortiori that there was probable cause to charge the defendants with the offenses for which they were convicted.” United States v. Mechanik, 475 U.S. 66, 67, 106 S.Ct. 938, 89 L.Ed.2d 50 (1986). Accordingly, “all but the most serious errors before the grand jury are rendered harmless by a conviction at trial.” Soto-Beniquez, 356 F.3d at 25 (internal quotation marks omitted). “ ‘Only a defect so fundamental that it causes the grand jury no longer to be a grand jury, or the indictment no longer to be an indictment’ is sufficient to invalidate a subsequent conviction.” Id. (quoting United States v. Reyes-Echevarria, 345 F.3d 1, 4 (1st Cir.2003)). None of the alleged errors before the grand jury rose to this level. With regard to the first claim, we note that the government denies the existence of any immunity agreements for the murders prior to the creation of supplemental cooperation agreements during trial. See infra at 33-38. Even if we were to assume that the agreements did exist, the prosecution’s failure to notify the grand jury thereof would not warrant dismissal of the indictment. Because of the nature of the grand jury’s function, “[t]he prosecutor before a grand jury is not normally under a duty to disclose exculpatory evidence. Nor ... is the prosecutor obligated to impeach the credibility of his own witnesses.” United, States v. Latorre, 922 F.2d 1, 7 (1st Cir.1990) (internal quotations omitted). Moreover, the petit jury’s conviction on the conspiracy count, made with knowledge that Pérez and Martinez were immune at trial and believed themselves to have been immune prior to trial for liability for the murders, leads us to seriously doubt “that a similarly informed grand jury would not have found probable cause.” United States v. Mangual-Corchado, 139 F.3d 34, 42 (1st Cir.1998). Next, neither the fact that the accounts of Pérez and Martinez contradicted each other in certain respects, nor that Martinez’s trial testimony went beyond the scope of his grand jury testimony, indicate that the prosecutor knowingly presented false testimony. See United States v. Lebon, 4 F.3d 1, 2 (1st Cir.1993) (“[T]he fact that a witness contradicts herself or changes her story does not establish perjury”); United States v. Doherty, 867 F.2d 47, 70 (1st Cir.1989) (finding no decision that “prohibits a prosecutor from calling witnesses who will present conflicting stories”); United States v. Hemmer, 729 F.2d 10, 17 (1st Cir.1984) (“Simply because there exist[s] inconsistencies between [a witness’s] grand jury and trial testimony does not warrant the inference that the government knowingly introduced perjurious testimony.”). Absent evidence of “prosecutorial misconduct that actually biases the grand jury in performing its fact-finding function,” United States v. Maceo, 873 F.2d 1, 3 (1st Cir.1989), we can go no further. An indictment returned by a legally constituted and unbiased grand jury “is not subject to challenge on the ground that the grand jury acted on the basis of inadequate or incompetent evidence.” United States v. Calandra, 414 U.S. 338, 363, 94 S.Ct. 613, 38 L.Ed.2d 561 (1974). For the same reason, we will not inquire into Casas’s claim that there was insufficient evidence before the grand jury of his participation in the overt acts listed in the indictment. A grand jury proceeding is not a trial; only after conviction following a trial is sufficiency of the evidence an appropriate issue. See, e.g., Reyes-Echevarria, 345 F.3d at 5. 3. Prosecutorial misconduct All six appellants claim that the proceedings below were infected with prosecutorial misconduct to such an extent that they were denied a fair trial. In determining “whether prosecutorial misconduct has so poisoned the well that a new trial is required,” we weigh several factors: “(1) the severity of the misconduct; (2) the context in which it occurred; (3) whether the judge gave any curative instructions and the likely effect of such instructions; and (4) the strength of the evidence against the defendant.” United States v. Manning, 23 F.3d 570, 574 (1st Cir.1994). Taking a “balanced view of the evidence in the record,” United States v. Rodríguez-De Jesús, 202 F.3d 482, 485 (1st Cir.2000), we evaluate the Manning factors to determine whether the misconduct likely affected the trial’s outcome. See Manning, 23 F.3d at 574. We have noted, however, that “[t]he remedy of a new trial is rarely used; it is warranted only where there would be a miscarriage of justice or where the evidence preponderates heavily against the verdict.” Rodríguez-De Jesús, 202 F.3d at 486 (internal quotation marks omitted). The district court denied a number of motions during and after trial for a mistrial, a new trial, and dismissal of the indictment on grounds of prosecutorial misconduct. (TT 8/24/99: 22-23, TT 9/30/99: 51, Docket No. 1671 (denied at Docket No. 1723); Docket No. 1910 (denied at Docket No. 1948); Docket No. 1911 (denied at Docket No. 2049); Docket No. 1912 (denied at Docket No. 2049); Docket No. 1951 (denied at Docket No. 2049); Docket No. 2272 (denied at Docket No. 2315)). Although we determine the legal question of whether the prosecutor’s actions constitute misconduct de novo, our review of whether the alleged misconduct requires a new trial is for abuse of discretion. United States v. Lewis, 40 F.3d 1325, 1337-38 (1st Cir.1994); United States v. Glantz, 810 F.2d 316, 320 n. 2 (1st Cir.1987); see also United States v. Mooney, 315 F.3d 54, 59 (1st Cir.2002) (motion for mistrial); Rodríguez De-Jesús, 202 F.3d at 485 (motion for new trial); United States v. Laboy, 909 F.2d 581, 585 (1st Cir.1990) (motion to dismiss indictment). Six alleged instances of prosecutorial misconduct are outlined below. Although some of the tactics employed by the prose-eutor’s office in its zeal to convict crossed the line of acceptable prosecutorial conduct, we conclude that none of the alleged actions likely affected the outcome of the trial. Accordingly, no new trial is warranted. a. Deception of Court Appellants all complain that the circumstances surrounding the sentencing of Pérez and Martinez resulted from an abuse of prosecutorial discretion insofar as prosecutors allegedly misled the probation department and sentencing courts about the Pérez’s and Martinez’s relevant conduct in order to secure their cooperation as witnesses against appellants. Pérez was indicted, along with the three individuals arrested for the March 21, 1994 attempt to smuggle cocaine through the Carolina airport, on a single charge of aiding and abetting in the possession with intent to distribute eighty-one kilograms of cocaine. After being captured as a fugitive in October 1994, Pérez chose to cooperate with prosecutors. On December 14, 1994, he entered into a plea agreement with the government, under which he received immunity in the District of Puerto Rico for “any other crimes committed (except crimes of violence such as, but not limited to, murder) about which [Pérez] has informed the United States.” The government agreed to recommend a Guidelines sentence with a base offense level (“BOL”) of 32, a three-level reduction for acceptance of responsibility under U.S.S.G. § 3E1.1, and a two-level reduction for having a minor role in the offense under U.S.S.G. § 3B1.2. The record reflects that by the time of Pérez’s sentencing on September 8, 1995, the prosecutor was aware that Pérez’s role in the larger conspiracy was far from minor, and that he had been involved in the murders of Blanco and de Jesús. Nonetheless, the prosecutor failed to bring information about the full extent of Pérez’s relevant criminal conduct to the attention of the probation department or sentencing judge, failed to inform the probation department or judge that financial and other information provided by Pérez for the pre-sentence report was inaccurate, and failed to object to the pre-sentence report’s recommendations of guidelines reductions for acceptance of responsibility and minor role. Accordingly, the sentencing judge accepted the plea recommendations, departing, on the government’s motion, even farther below the Guidelines range for substantial assistance under U.S.S.G. § 5K1.1. The resulting sentence was for sixty months’ imprisonment. Martinez was indicted along with appellants and eventually agreed to plead guilty to Count Four (aiding and abetting in the possession with intent to distribute thirty-six kilograms of cocaine). The government agreed to a sentence based on 4.9 kilograms of cocaine, with a three-level reduction for acceptance of responsibility under U.S.S.G. § 3E1.1 and an additional two-level reduction if the “safety valve” provisions of 18 U.S.C. § 3553(f) and U.S.S.G. § 5C1.2 were found to apply. Among other things, the “safety valve” requires that “the defendant did not use violence or credible threats of violence ... in connection with the offense; [and] the offense did not result in death or serious bodily injury to any person.” 18 U.S.C. § 355S(f)(2)-(3). Although AUSA Miguel Fernández had been present at Martinez’s grand jury testimony concerning his participation in the Blanco and de Jesus murders (Appendix: 168, 172-79), the government’s motion requesting downward departure represented that Martinez did qualify for the “safety valve.” (Appendix: 83). The government did not inform the sentencing judge— who also presided at appellants’ trial — of the extent of Martinez’s participation in the drug trafficking conspiracy, nor of his participation in the Blanco and de Jesús murders. (TT 9/30/99: 48). On February 26, 1998, Martinez was sentenced to twenty-four months’ imprisonment. It appears that the prosecutors misled the probation department and the sentencing courts as to the sentences of Pérez and Martinez. Prosecutors have a duty of candor to the court. See ABA Model Rules of Profl Conduct R. 3.3 (2002). That does not mean that these defendants/appellants have any right to complain about what happened with other defendants. But even if we assume that the Manning factors can be used when the purported misconduct is not directed against appellants themselves, the context in which it occurs — the sentencing of cooperating defendants — renders it unlikely to have affected the outcome of appellants’ trial. Further, while the courts that sentenced Pérez and Martinez may not have been aware of the full extent of their involvement in the drug conspiracy, the nature of both witness’ activities within the organization, including their involvement in the murders, came out in their testimony on direct and cross-examination. The evidence that they received lenient sentences in exchange for their cooperation with the government was exploited by the defense for its impeachment value. (TT 6/7/99: 23-36; TT 9/24/99: 12-16, 73-104). The jury was also presented evidence indicating that these sentences resulted from the government’s failure to present all relevant evidence to the probation department and sentencing judges, in the form of testimony from the probation officers involved in preparing Pérez’s and Martinez’s pre-sentence reports and the federal prosecutor who handled Pérez’s plea agreement and sentencing. Pérez was also cross-examined with regard to his PSR and admitted that he lied to the probation officer who prepared it. (TT 6/15/99: 79). Thus, we cannot conclude that the government’s misconduct in securing low sentences for its cooperating witnesses likely affected the outcome of appellants’ trial to their detriment. b. Failure to disclose immunity agreements Appellants next argue that the government improperly withheld information about cooperation agreements it granted to cooperating witnesses. The government responds that no such agreements were withheld and that defendants suffered no prejudice insofar as the details of all cooperation agreements were available for use during cross-examination of the cooperating witnesses. During arguments outside the presence of the jury about whether the Blanco and de Jesús murders were part of the charged conspiracy, defense counsel inquired as to whether Pérez had been given immunity for his participation in the murders. (TT 5/26/99: 67). Quoting from Pérez’s plea agreement, which granted immunity in the District of Puerto Rico “except for crimes of violence such as but not limited to murder,” the government argued that Pérez did not have immunity. (TT 5/26/99: 75-76). The district court ordered Pérez and Martinez to appear in court, with representation, in order to be advised of their exposure to prosecution and right not to testify to the murders. (TT 5/28/99: 3). Prior to this appearance, the prosecutor indicated to Pérez’s legal representative that his office did not intend to charge Pérez with the murders, on account of an internal policy against indictments based on uncorroborated witness statements. (TT 5/28/99: 23-28). Shortly thereafter, supplemental cooperation agreements granting immunity from prosecution in Puerto Rico, and the federal District of Puerto Rico, the Southern District of Florida, and the Southern District of New York for the two murders were negotiated with both Pérez and Martinez. (Appendix: 107). Both supplemental agreements were presented in court and provided to the defense. (TT 6/3/99: 4-5; TT 9/21/99: 9-10). During cross-examination on June 7, 1999, however, Pérez stated that he began providing the government information about the murders prior to the written immunity agreement because Agent Stoo-thoff had verbally informed him that he would not be prosecuted for the murders. (TT 6/7/99: 30-33). No such verbal immunity agreement was brought to the attention of the defense prior to trial. When he was recalled as a defense witness, Agent Stoothoff denied having made such a promise. (TT 10/28/99: 18). About two months after Pérez testified, another former member of the drug trafficking organization, Martfnez-Medina, was called as a government witness. The following exchange occurred at the beginning of his testimony: Q. Okay. Did you enter your guilty plea by way of a common plea agreement or a cooperation plea agreement? A. There was no agreement. THE COURT: Didn’t he say there was no plea agreement? [PROSECUTOR]: No cooperation and plea agreement but just a plea agreement, a regular plea agreement. (TT 8/19/99: 50-51). On cross examination, however, Martinez-Medina testified that, while he had no written cooperation agreement, he had a verbal agreement with AUSA Mercado wherein he understood that the government would consider filing for a reduction of his sentence in exchange for his testimony. (TT 8/24/99: 52-53). The prosecutor acknowledged that a motion had been filed, and granted, for an extension of the time based on an intent to request a sentence reduction in Martínez-Medina’s case. (TT 8/24/99: 62; TT 8/25/99: 9). The defense moved for a mistrial on the basis that it could not be known whether other witnesses who had already testified also had undisclosed verbal cooperation agreements. (TT 8/24/99: 66). Chastising the prosecutors for their failure to formalize such agreements in writing and to disclose them to the defense, the district judge denied the motion, finding that defendants’ rights could be fully redressed by having the prosecutors file representations with regard to each witness who had already testified concerning the existence of any unwritten cooperation agreements, and by reopening cross-examination to the defense on any such agreements. (TT 8/24/99: 69-72). The court instructed prosecutors to confer with other AUSAs who had worked on the case to ensure that no cooperation agreements were overlooked, and to disclose any such agreements not only for past witnesses, but also for upcoming witnesses. (TT 8/24/99: 69-72). The court instructed the jury, at the defense’s request and using its proposed language, that “the prosecution had the duty to reveal the existence of [Martinez-Medina’s cooperation] agreement and failed to do so. For that reason, the Court shall reopen the cross examination of this witness ... solely to allow the defendants to examine him on that particular aspect.” (TT 8/25/99: 13). No disclosure of any unwritten cooperation agreement was made with regard to Martinez. However, when he testified in September 1999, he at first stated that he did have a verbal agreement with the government, prior to the written immunity created during trial, that he would not be prosecuted for the Blanco and de Jesús murders. (TT 9/24/99: 76-82). When questioned later, however, he stated that he did not have such an agreement and did not know why he had testified otherwise before. (TT 9/27/99: 36). The court denied another motion for mistrial, which was based in part upon the prosecution’s failure to disclose the verbal cooperation agreements, on September 30, 1999. (TT 9/30/99: 12,37,51). Suppression of evidence favorable to the defense violates due process. Brady v. Maryland, 373 U.S. 83, 87, 83 S.Ct. 1194, 10 L.Ed.2d 215 (1963). The Brady rule applies to evidence affecting key witnesses’ credibility, Giglio v. United States, 405 U.S. 150, 153-54, 92 S.Ct. 763, 31 L.Ed.2d 104 (1972), and thus would encompass the verbal cooperation agreements discussed above. While we note that Agent Stoothoff denied having promised that Pérez would not be prosecuted for the murders, knowledge of any such promise, if it existed, would be imputed to the prosecution, along with knowledge of the promise made by AUSA Mercado to Martinezr-Medina to consider a sentence reduction if he testified against appellants. See id. at 154; Kyles v. Whitley, 514 U.S. 419, 437, 115 S.Ct. 1555, 131 L.Ed.2d 490 (1995). However, “[w]hen the [Brady/Giglio ] issue is one of delayed disclosure rather than of nondisclosure, ... the test is whether defendant’s counsel was prevented by the delay from using the disclosed material effectively in preparing and presenting the defendant’s case” ... [and][w]e review the district court’s decision on how to handle delayed disclosure of Brady material for abuse of discretion. United States v. Catano, 65 F.3d 219, 227 (1st Cir.1995) (quoting United States v. Ingraldi, 793 F.2d 408, 411-12 (1st Cir.1986)), Here, the defense was not prejudiced in its ability to use the existence — or, at any rate, the three cooperating witnesses’ belief in the existence — of verbal cooperation agreements to call the cooperating witnesses’ credibility into question. While the government denies having made any such agreements with Pérez and Martinez, it is clear that the government indicated to Martinez-Medina that a reward for cooperation would be considered. Accordingly, the representation during direct examination that no cooperation agreement existed was, at best, misleading, and we strongly condemn the prosecution’s failure to correct the statement or to disclose the existence of a cooperation agreement as required by Giglio. However, for each witness, the existence, confirmed or otherwise, of the verbal cooperation agreement came out during cross-examination and was sufficiently investigated by the defense. See United States v. McGovern, 499 F.2d 1140, 1143 (1st Cir.1974) (finding no prejudice from late disclosure of cooperation agreement because it occurred while witness was still on the stand and court allowed further cross-examination). No prejudice resulted to defendants. Although the misconduct, at least with respect to the Martinez-Medina agreement, was serious, we find that it was unlikely to have affected the outcome of trial when considered in light of the opportunity for cross-examination and the curative actions taken by the court. We thus find no abuse of discretion in the district court’s denial of a mistrial on the basis of the late disclosure of these agreements. c. Violation of sequestration orders Nicolai, Correy, and Pizarro argue that the government engaged in misconduct by violating witness sequestration orders. On May 26, 1999, Pérez was testifying but had not yet testified about the Blanco and de Jesús murders. (TT 6/2/99: 82). Pending before the court at that time was the issue of whether the murders were a part of the charged conspiracy. While carrying out his duties to escort Pérez to and from court, Agent Stoothoff discussed with him factual issues relevant to the potential connection. (TT 6/2/99: 83-84). The defense argued that this conversation violated the court’s order that Pérez not discuss his testimony with anyone else and sought to prohibit Pérez from later testifying about the murders. Upon reviewing notes taken by the prosecutor during a November 1995 interview in which Pérez gave the same information that he later discussed with Agent Stoothoff, the district court determined that the sequestration order had been violated but that no prejudice resulted because the conversation did not alter Pérez’s testimony. (Docket No. 1294). The order also admonished that any future contact between the government and testifying witnesses concerning matters about which they would testify would result in the exclusion of such testimony. (Docket No. 1294). Appellants have not indicated that additional violations occurred. We find no abuse of discretion in the district court’s determination that defendants suffered no prejudice as a result of the violation of its somewhat ambiguous sequestration order. d. Offering false testimony Nicolai, Pizarro, and Correy assert that the government presented testimony at trial that it knew or should have known was false. Nicolai’s and Pizarro’s claims are readily disposed of, as they are based on the government’s presentation of Pérez’s and Martinez’s conflicting accounts of the Blanco and de Jesús murders. The government violates due process when it obtains a conviction by soliciting or failing to correct false evidence. Napue v. Illinois, 360 U.S. 264, 269, 79 S.Ct. 1173, 3 L.Ed.2d 1217 (1959). However, “[n]either Napue nor any other decision prohibits a prosecutor from calling witnesses who will present conflicting stories.” United States v. Doherty, 867 F.2d 47, 70 (1st Cir.1989). As the district court correctly recognized, such conflicts are a matter to be explored on cross-examination (Docket No. 1276: 7), and the credibility of each account is for the jury to determine. In addition, we find that appellants were not prejudiced by the conflicting testimony, which differed in its description of Pérez’s, not the charged defendants’, actions during the murders. The defendants charged with the murders were acquitted, demonstrating that the contradictory testimony likely undermined the credibility of both key prosecution witnesses. Correy also raises a number of inconsistencies that fall far short of showing that the witnesses in question perjured themselves, much less that the government knowingly allowed them to do so. First, Correy refers to Martinez-Medina’s testimony that misleadingly implied he had received no consideration for his cooperation with prosecutors. We have already addressed this issue above. See supra at 35-38. Correy also cites Agent Stoothoff s assertion, during his direct testimony as a defense witness, that he saw an American Airlines flight manifest that indicated that Correy and others flew to Puerto Rico immediately prior to the Blanco and de Jesús murders. (TT 10/28/99: 64-67). The government, however, was no longer in possession of the manifest, and Correy asserts that the manifest would have been destroyed according to the airline’s document retention procedures long before Agent Stoothoff claims he obtained it. Correy has not shown that Stoothoff lied about seeing the manifest, however, and even if he had, the testimony was stricken and the jury was instructed to disregard it as violative of Federal Rule of Evidence 1003. (TT 10/28/99: 131-32,136). Correy alleges two other instances of perjury or prosecutorial misconduct. The first is Agent Stoothoff s incorrect assertion that another investigator, who later testified to the contrary (TT 11/23/99: 31), told him a dive team had searched for evidence of the Blanco and de Jesús murders. The second is cooperating witness Vélez’s testimony that Correy participated in a drug transaction despite his failure, when debriefed by investigators, to mention Correy’s participation and Martinez’s conflicting testimony that Correy was not present for that particular transaction. Neither instance demonstrates perjury or prosecutorial misconduct. [T]he government is not forbidden to call witnesses whose reliability in one or many particulars is imperfect or even suspect. Its obligations are to make a clean breast of any evidence it has which may contradict such witnesses or undermine their credibility, and not to rest its case upon testimony which it believes to be incorrect. McGovern, 499 F.2d at 1143; See generally Lebon, 4 F.3d at 2 (“[T]he fact that a witness contradicts herself or changes her story does not establish perjury.”); Doherty, 867 F.2d at 70 (finding no decision that “prohibits a prosecutor from calling witnesses who will present conflicting stories”). e. Preservation of evidence Bonilla argues that he was prejudiced by the government’s failure to preserve evidence — bullet casings and a bloody shirt — taken from the scene of the Blanco and de Jesús murders. Bonilla was not charged in the murder counts, but argues that the evidence might have helped to impeach the credibility of Pérez by showing that Martinez’s account of the murders was true and Pérez had lied about his involvement. Bonilla’s position relies on the speculative reasoning that the bullet casings might have been traceable to Pérez’s weapon, or that Pérez’s DNA might have been found on the shirt, thereby demonstrating that Pérez lied about not shooting the victims. Neither of these outcomes appears likely from Martinez’s account, which was that Correy and Nico-lai used weapons provided by Pizarro to shoot the victims inside a rental car and then Nicolai used a t-shirt to wipe fingerprints from the interior. (TT 9/21/99: 85-95). Moreover, Pérez’s credibility had already been called into serious question by the discrepancy between his and Martinez’s accounts of the murders. Accordingly, we find that Bonilla was not prejudiced by the apparently inadvertent loss of the casings and shirt. Bonilla also claims prejudice from the government’s failure to maintain an electronic organizer in operating condition, resulting in the admission instead of an investigator’s partial transcription of its contents. The claim is without merit. The organizer was nonfunctional because its batteries were dead, and rather than risk losing data by changing the batteries, investigators transcribed its contents before it lost power. The district court considered and overruled objections to admitting the transcribed information, holding that there was no evidence of intentional tampering and that the incomplete record of the contents was a topic appropriate for cross-examination. (TT 5/21/99: 67). We find no abuse of discretion in the ruling, nor prosecutorial misconduct in the use of the transcription. f. Inappropriate gestures Correy claims that the prosecution attempted to influence witnesses and the jury by making inappropriate gestures in open court. Correy points to three instances in particular. On June 14, the prosecution objected to Nicolai’s (who was conducting a cross-examination pro se) allegedly turning and making a face at the prosecution table when he received a favorable ruling. In the resulting sidebar, Nicolai and others on the defense alleged that the prosecutors had also been gesturing, nodding or otherwise showing satisfaction with favorable testimony and attempting, through rapid-fire objections, to throw Nicolai off. The court admonished all parties to behave. (TT 6/14/99: 23-29). On September 1, the defense objected that a law enforcement officer seated at the prosecution table was blatantly “coaching” Pér-ez as he testified, through gestures. The trial judge witnessed some of these gestures, and, though she did not conclude whether they were voluntary or inadvertent, admonished the officer to stop making any gestures that could be interpreted by the witness as direction. (TT 9/1/99: 65-73). During the sidebar discussion of this incident, Nicolai and others on the defense again suggested that AUSA Fer-nández was attempting to throw Nicolai off by, for example, tapping his pen loudly. The court once again admonished all counsel to behave appropriately. (TT 9/1/99: 65-73). Finally, on October 26, the defense raised concerns that the behavior of the prosecutor demonstrated a lack of respect for the court’s authority and might lead the jury to conclude that the government attorneys enjoyed more latitude than defense counsel. The judge was aware of two such instances, one in which she had to admonish the prosecutor to abide by an evidentiary ruling, and another in which the prosecutor threw his pen after receiving an adverse ruling. She admonished him to keep his behavior in check and to respect the court’s authority. (TT 10/26/99: 175-77). The trial judge was in a far better position than we to determine whether the alleged gestures and other behavior occurred, whether they appeared to be intentional or inadvertent, and whether they had any influence on witnesses or the jury. We will not second-guess her rulings on the record before us. With regard to those gestures that the court did observe — nodding at the witnesses, disregarding a ruling, and throwing a pen— whether they were intentional or not, they were unprofessional and inappropriate. However, they occurred in the context of a seven-month jury trial, were addressed by admonishments from the court, and, from the record, do not appear to have prejudiced Correy or the other defendants. Within the overall framework of this lengthy trial, they were unlikely to have affected the outcome of trial. Thus, they fall short of rendering the trial so unfair as to require a new one. In sum, we find that none of the alleged ’ instances of prosecutorial misconduct was likely to have affected the outcome of the trial, and thus none requires a new trial. To be sure, “[ijndividual errors, insufficient in themselves to necessitate a new trial, may in the aggregate have a more debilitating effect.” United States v. Sepúlveda, 15 F.3d 1161, 1195-96 (1st Cir.1993). The prosecution’s initial failure to disclose the unwritten cooperation agreement it created with Martinez-Medina, along with the less disconcerting but still inappropriate violation of Pérez’s sequestration order and the government’s courtroom behavior all reflect poorly on the conduct of the prosecution. However, when viewed “against the background of the case as a whole,” id. at 1196 — a seven-month trial of ten defendants on charges stemming from a large and lengthy drug-trafficking conspiracy, during which the trial judge diligently addressed and effectively corrected for errors as they were brought to her attention — the fairness of the trial was not compromised. Finally, we note that although “[w]hen confronted with extreme misconduct and prejudice” we may “invoke [our] supervisory powers to remedy the violation of a recognized right, preserve judicial integrity, and deter illegal conduct” by ordering a new trial, we cannot do so “[without a nexus between improper prosecutorial practice and prejudice to the defendant.” United States v. Osorio, 929 F.2d 753, 768 (1st Cir.1991); see also Bank of Nova Scotia v. United States, 487 U.S. 250, 254-55, 108 S.Ct. 2369, 101 L.Ed.2d 228 (1988). We cannot therefore consider action to penalize the tactics employed in this case because appellants were not prejudiced by the prosecutor’s actions. 4. Juror misconduct During a trial recess, a court officer heard one of the jurors say that she was jealous and heard another juror explain that it was because Nicolai’s wife was in the courtroom. The trial judge decided, over the objection of appellants, to further investigate the matter by interviewing the juror in question. Although the juror initially denied the comment, she eventually made a number of assertions that raised concerns about jury bias, including that some female jurors “liked” certain defendants, that she knew Nicolai was in jail, and that jurors had expressed the opinion that Nicolai was a “cabesilla [sic]” (kingpin) of a gang. Her responses also suggested that the jurors might prematurely have begun deliberating about the trial by discussing the evidence presented and whether certain defendants should be convicted. Following the interview, several defendants moved for a mistrial. The court denied that motion, opting instead to voir dire each member