Full opinion text
CARL E. STEWART, Circuit Judge: Joseph Ebron was sentenced to death for the murder of a fellow inmate. He now appeals his conviction and sentence. In addition, he is also challenging the district court’s denial of his motion for a new trial. For the following reasons, we affirm his conviction, sentence, and the denial of his motion. I. A. 1. On May 6, 2005, Keith Barnes, an inmate from Washington D.C., arrived at the United States Penitentiary in Beaumont, Texas. When Barnes arrived at USP-Beaumont, he met with a case manager for an intake screening before being assigned to a cell block. During the screening, Barnes told the case manager he had testified against his codefendants in two 1998 murder trials in Washington D.C., and was concerned about his safety because other inmates from the D.C. area might have been aware of his cooperation. Notably, one of his codefendants was James Carpenter. Despite this voiced concern, Barnes was placed in the prison’s general population. The following day, Barnes was found dead on the top bunk of the bed in his cell. Barnes’s autopsy revealed that he had died of multiple stab wounds. Specifically, his autopsy indicated that he was stabbed 106 times by a sharp, round instrument in an eight-inch by four-inch area over his heart, left lung, and liver. On May 8, 2005, prison officials conducted mass interviews of inmates to gather more information regarding Barnes’s murder. During these interviews, Charles Sherman, another inmate from Washington D.C., identified Ebron, Marwin Mosley, and Michael Bacote as fellow participants in Barnes’s murder. At trial, the jury heard two competing narratives of what occurred on May 7th. These narratives are captured in the testimony of two witnesses: Sherman and Ebron. 2. In 2005, Sherman was serving a sentence for armed robberies he committed in Washington D.C. and was being housed in the Delta Bravo unit of USP-Beaumont. According to Sherman, the following events took place upon Barnes’s arrival. In prison, inmates from particular states tend to form groups for protection. When inmates arrive at USP-Beaumont, they are approached by fellow inmates and asked questions about “where [they are] from.” Once this information is gathered, the newly arrived inmate is pointed in the direction of other inmates who are from the same geographic area. After Sherman learned of Barnes’s arrival, he, Bacote, and Mosley approached Barnes. When they first met Barnes, he did not tell them his real name; instead, he gave an Arabic name. At the conclusion of this meeting, Barnes went to his cell, which was also located in Delta Bravo. Sherman, Bacote, and Mosley then proceeded to have a conversation about Barnes. During this conversation, Mosley told the group that he did not believe that the Arabic name Barnes provided was his actual name. Mosley informed the group that he recognized the new inmate and thought his name was Keith Barnes. When Sherman asked Mosley for the basis of his familiarity with Barnes, Mosley stated that he “believe[d] [Barnes] testified on some good dudes at DC jail.” Mosley specifically identified Carpenter as one of those “good dudes.” After suspecting that the new inmate was actually Keith Barnes, Mosley told Sherman and Bacote to find out the new inmate’s real name. The following morning, Bacote tricked Barnes into providing his real name. Later that morning, Sherman and Bacote told Mosley that the new inmate was indeed Barnes. Upon receiving confirmation of his suspicion, Mosley told the group to follow him to the recreation yard to talk to Tone, the leader of the D.C. group at USP-Beaumont. The purpose of Mosley’s visit with Tone was to inform him of his plan to kill Barnes. Mosley, Sherman, and Bacote went out to the yard during their next opportunity. Mosley then proceeded to have a conversation with Tone in which he told Tone that Barnes had testified against his friend, Carpenter. Tone then told them to beat Barnes up and force him to request segregation from the general prison population. Mosley responded to this suggestion by stating, “No, we’re going to kill him ... I’m going to kill him.” Tone replied by telling Mosley that killing Barnes was unnecessary; all they needed to do was beat him up and force him to request to be segregated. Mosley rejected this suggestion and told Tone that he was going to kill Barnes that night. When Mosley, Sherman, and Bacote left the yard, they went back to Delta Bravo and started discussing how Barnes would be killed. While back in Delta Bravo, they decided to kill Barnes in his cell. Specifically, they appeared to agree that Bacote would go into Barnes’s cell to discuss the Koran, and that Ebron and Mosley would then enter the cell to kill Barnes. After lunch, Mosley, Sherman, and Ba-cote set out to look for Ebron, and located him on a walkway heading towards Delta Bravo. Mosley and Bacote then had a conversation with Ebron in which they told him about Barnes’s presence at USP-Beaumont. Mosley told Ebron about the plan to Mil Barnes and asked for his help. Ebron agreed to participate. Bacote subsequently jumped in the conversation and told Ebron to wrap his shirt over his head when he entered Delta Bravo in order to avoid detection by surveillance cameras. After this conversation, Mosley, Sherman, and Bacote went back to Delta Bravo to continue discussing how to Mil Barnes. Once dinner was called, Ebron entered Delta Bravo and, at some point, Bacote went into Barnes’s cell. When Sherman saw Ebron in Delta Bravo around dinnertime, Ebron had his khaki shirt wrapped around his head. Ebron and Mosley subsequently entered Barnes’s cell. After Ebron and Mosley entered the cell, Bacote exited and situated himself on some stairs that were outside of Barnes’s cell. Sherman subsequently joined Bacote on these stairs. From these stairs, Sherman was able to look into Barnes’s cell. When he looked in, he saw Ebron holding Barnes in a headlock, while Mosley’s arms were “motioning.” This observation was consistent with their plan to Mil Barnes: Ebron was to hold Barnes while Mosley stabbed him. After a couple of minutes, the door to Barnes’s cell opened. Sherman then walked over and closed the door. As he closed the door, Sherman could see Mosley and Ebron lift Barnes up and place him on the top bunk of the bed in his cell. A few minutes after Sherman closed the door, Ebron and Mosley emerged from Barnes’s cell and went their separate ways. 3. In 2005, Ebron was serving his sentence for a murder that occurred in Washington, D.C. During the relevant time period, Ebron was housed in the Alpha Alpha unit of USP-Beaumont. According to Ebron, the following events occurred on the day of Barnes’s murder. During the afternoon of May 7th, Ebron was walking back to Alpha Alpha when he was approached by seven D.C. inmates, including Sherman, Bacote, and Mosley. As Mosley and Ebron walked toward Alpha Alpha, Mosley mentioned Keith Barnes and asked Ebron if Carpenter, who at one point was Ebron’s cell mate at USP-Atlanta, ever said anything about Barnes testifying against Carpenter. Ebron responded by stating that he did not know the whole situation, but heard that Barnes and Carpenter were “worMng it out.” After hearing Ebron’s response, Mosley again asked Ebron whether Barnes had testified against Carpenter. This time, Ebron provided an unequivocal affirmative answer. Upon hearing this, Mosley told Ebron that he was “going to put the knife in [Barnes].” Ebron then suggested to Mosley that stabbing Barnes was unnecessary. Instead of stabbing Barnes, Ebron indicated that all they had to do was convince Barnes to request segregation. Mosley did not agree with this suggestion — he thought it “was too easy for Keith Barnes.” Despite Mosley’s disagreement, Ebron continued trying to convince Mosley that stabbing Barnes was unnecessary. After Ebron rejected Mosley’s suggestion that, at the very least, they beat Barnes up, Mosley told Ebron to get Barnes out of Delta Bravo that day. Ebron agreed to do so. Not long after 5:00 p.m., Ebron left Alpha Alpha and entered Delta Bravo. Despite being prohibited from entering another unit, Ebron made his way into Delta Bravo and concealed his identity by placing his khaki shirt on his head. Once inside Delta Bravo, Ebron met up with Mosley and asked him where Barnes was located so that he could walk Barnes to the lieutenant’s office. Once there, Barnes would then request administrative segregation and thus be removed from Delta Bravo. Rather than telling Ebron where Barnes was located, Mosley began mentioning pictures that he and Ebron had previously talked about. Mosley and Ebron then went into Mosley’s cell to view these pictures. After a few minutes, Ebron again asked Mosley about Barnes. In response, Mosley told Ebron that they were going to walk Barnes to the lieutenant’s office. Mosley then left his cell and walked towards Barnes’s cell; Ebron followed him. Before entering Barnes’s cell, Ebron told Mosley to “chill out” and to let him do the talking. Because Mosley had previously revealed his preference to beat Barnes up, Ebron wanted to make clear that they were not going to physically harm Barnes. When they entered the cell, Bacote and Barnes were having a conversation. As soon as he entered Barnes’s cell, Mosley walked behind Barnes; Ebron stood by the front of the cell. Before exiting the cell, Bacote introduced Ebron as Barnes’s “Sunni Muslim brother.” After Ebron asked Barnes a couple of questions, Mosley jumped into the conversation and started asking Barnes questions about Barnes’s case and his codefendants. Ultimately, Mosley got Barnes to admit that he was indeed Keith Barnes. In response to this admission, Mosley stated, “Yeah. You a snitch.” Mosley then declared that Barnes needed to be removed from the general population. Upon hearing this, Barnes turned to Ebron and stated, “Akhee. I just talked to the Muslims. They gave me my protection — they gave me their protection.” As soon as Barnes made this statement, Ebron wanted to get out of the cell and talk to Barnes in private. After Ebron and Barnes agreed to leave Barnes’s cell, Mosley punched Barnes on the side of his head. This blow caused Barnes to fall on the bottom bunk of the bed located in his cell. Once Barnes was on the bed, Mosley jumped on Barnes, straddled him, and started stabbing him with a chrome knife that was tied around his fist. Barnes fought back against Mosley, but could not stop Mosley in his quest to “stab [Barnes’s] heart out.” According to Ebron, he did not participate in the assault. Indeed, not only did Ebron plead with Mosley to stop stabbing Barnes, but he also refused Mosley’s request for help in subduing Barnes. After he made sure that Barnes was dead, Mosley hopped off Barnes’s corpse, grabbed a towel, and unsuccessfully attempted to close the cell door. Mosley then yelled outside the door and requested assistance in closing the cell door. The door was closed from the outside after Mosley made his request. When the door closed, Mosley confronted Ebron and asked him why he did not assist in Barnes’s murder. In response, Ebron stated that he “wasn’t trying to be part of no murder.” After feeling threatened by Mosley, Ebron agreed to help Mosley place Barnes’s body on the top bunk. Mosley then washed his hands, cleaned off his knife, and wiped down areas he may have touched. Mosley and Ebron then left the cell. B. On August 15, 2007, a federal grand jury returned a two-count indictment against Ebron, Bacote, and Sherman. Count I of the indictment charged the defendants with murder; Count II charged them with conspiracy to commit murder. In September 2007, the government filed a Notice of Intent to Seek the Death Penalty against Ebron. Of the three defendants, only Ebron faced the possibility of a death sentence. On March 19, 2008, the district court severed Ebron’s trial. Before trial, the district court also decided to divide Ebron’s trial into three phases: guilt/innocence, eligibility for the death penalty, and selection of a sentence. C. 1. a. After seven days of individual voir dire, twelve jurors and five alternates were empaneled. The empaneled jurors started hearing evidence on April 20, 2009. On this day, the government had Sherman testify to his version of what occurred on the day of Barnes’s murder. The following day, the prosecution also presented the testimony of two inmates who provided additional details of the activity that took place in Delta Bravo after Barnes arrived at USP-Beaumont. One of these inmates, Johnny Bazile, testified that, on the night of Barnes’s murder, Bacote told him, in a rambling manner, that Ebron and Mosley had “punished” Barnes. Bazile also testified that Bacote told him that Bacote had held Barnes “to stop him from hollering.” That same day, the jury heard testimony from Robert Nylen, an intelligence specialist for the Federal Bureau of Prisons who, on the day of Barnes’s murder, reviewed USP-Beaumont’s surveillance camera footage. At trial, the government showed the surveillance camera footage to the jury while Nylen provided testimony regarding his understanding of what was taking place in the footage. In his testimony, Nylen stated that the video footage captured Ebron entering and exiting Barnes’s cell. Additionally, Nylen also testified that a portion of the video capturing Bacote raising his arm before Ebron and Mosley entered Barnes’s cell actually depicted Ba-cote giving Ebron and Mosley a “thumbs up.” On April 28, 2009, Dr. Tommy Brown testified on behalf of the government. In his testimony, he opined that the wounds found on Keith Barnes’s body were consistent with a victim being restrained from behind while being stabbed from the front. Beginning on this day and carrying over to April 24th, the government presented witnesses who testified about three separate incidents where Carpenter and Ebron engaged in collaborative acts of violence. These witnesses — Tim Zuppinger, Leander White, and Steven Perry — stated that while at USP-Atlanta, Carpenter and Ebron worked together in beating up two inmates in three separate incidents. The government used these individuals as Federal Rule of Evidence Rule 404(b) witnesses to prove similar acts that, according to the government, showed that Ebron had the motive and intent to harm Barnes because he had testified against Carpenter. On April 28, 2009, the government placed Lamont Bailey, another D.C. inmate, on the witness stand. In his testimony, Bailey stated that in July 2005, Mosley told him that Mosley and “Akh” killed Barnes because he had served as a government witness. Over the course of developing its case, the government also presented the testimony of three Bureau of Prisons officials — Carl Powers, Derric Wilson, and Eric Rayburn — who discussed various aspects of penitentiary life, prisoner behavior, and inmate-on-inmate violence. Once the government concluded its casein-chief, the defense presented four witnesses. Three of these witnesses warrant mention. First, Carpenter took the stand and testified about his relationship with Ebron, the USP-Atlanta fights, and his need for Keith Barnes to testify in a habeas petition he had initiated. Second, Dr. Steve Pustilnik provided expert testimony supporting Ebron’s version of what occurred in Barnes’s cell. Specifically, Dr. Pustilnik testified that “[Barnes] could easily have been restrained by one party by their body weight on top of him and having then delivered all of [the] wounds to him in this one focal area, in the upper abdomen and left side of his chest.” Third, Ebron took the stand and recounted his version of what took place on May 7, 2005. In its rebuttal case, the government presented Paul Wingate. At trial, Wingate stated that he served as one of the detectives on the case in which Barnes testified against Carpenter. During his investigation in that case, Wingate obtained several letters written by Carpenter. While on the witness stand, Wingate read from some of these letters. In one of these letters, Carpenter wrote, “Anger, I don’t get mad. I get even. I can’t say I be angry, but I do live for revenge.” In another, Carpenter mentioned that Barnes had given a “bad statement.” In a third letter, Carpenter wrote the following to Barnes: “[I]f you lose the case, you’re going to have enemies you didn’t even know or you didn’t even do nothing to.” Despite objections, the district court admitted these letters to prove Ebron’s motive in killing Barnes and to show inconsistencies in Carpenter’s testimony. b. The jury started deliberating at approximately 4:00 p.m. on Thursday, April 30, 2009. The following day, at around 3:30 p.m., the jury submitted a note to the district court stating the following: “The jury is hopelessly deadlocked. It cannot reach a unanimous verdict.” In response, the district court instructed the jury to continue their deliberations. At the end of this day, the district court informed the jury that there would be a three-day break in deliberations. The jury reconvened on Thursday, May 7th. On this day, the jury sent another note to the district court which stated, “There is no way we can arrive at a unanimous decision. I don’t believe any amount of further deliberation will achieve any movement. There’s been no change since Friday morning. I can discuss this with you privately if you wish.” After receiving this note, the district court read the jury the modified Allen charge contained in the Fifth Circuit pattern jury instructions. A little over an hour after the reading of the modified Allen charge, the jury sent a note to the district court requesting an easel and a flip chart. Later that same day, it requested a transcript of Ebron’s trial testimony. Because a transcript was unavailable, Ebron’s testimony was read back to the jury in its entirety. The following day, on Friday, May 8, 2009, the district court received a note from a juror, Brittany Johnson, who did not reenter the jury room after lunch. Johnson’s note specifically stated that other jurors had cursed at her and that the situation in the jury room was extremely stressful for her. In addition, Johnson’s note mentioned that the jury was hung and that it had deliberated thoroughly. After reading this note, the district court asked Johnson to “return to the jury room and follow [its] instructions.” At this point, Ebron unsuccessfully moved for a mistrial based on this communication and the two previous notes that were sent from the jury. Later that day, the district court received another note from a juror. In this note, a juror requested part of the following Tuesday off to attend an awards breakfast. The district court denied this request. Notably, however, this note prompted a discussion between the attorneys and the district court regarding the jury’s deliberations. At the end of this discussion, the attorneys agreed that the district court should question the foreperson to ascertain whether the jury was still deliberating. The district court agreed to do so. Once the foreperson arrived in the courtroom, the district court began questioning him. When asked whether any juror was refusing to follow the district court’s instructions, the foreperson answered in the affirmative. In addition, when asked about the perceived basis for the refusal to follow instructions, the foreperson stated that it was something other than a different view as to the weight of the evidence. In subsequent responses, the foreperson identified Brittany Johnson as the juror in question, and also indicated that Johnson had made a comment about defense counsel, Katherine Scardino. Based on this information, the district court decided to question the remaining jurors to investigate the allegation made by the foreperson. Before the remaining jurors were questioned, Ebron unsuccessfully moved for a mistrial. After questioning the remaining jurors, the district court dismissed Johnson for “bringing personal feelings to bear, based on personal experiences, into the trial and for making comments about one of the lawyers in the case[.]” Once Johnson was dismissed, she was replaced with an alternate. That weekend, Ebron filed a written motion for a mistrial based on Johnson’s removal. In a memorandum and order dated May 18, 2009, the district court denied Ebron’s motion. The reconstituted jury began its deliberations on Monday, May 11, 2009. It deliberated for approximately five hours before returning a guilty verdict on both counts. 2. The eligibility phase of the trial started immediately after the guilty verdict was read. The government submitted the following three statutory aggravating factors to support Ebron’s eligibility for the death penalty: (1) having a “[pjrevious conviction of offense for which a sentence of death or life imprisonment was authorized”; (2) the “heinous, cruel, or depraved manner of committing [his] offense”; and (3) “substantial planning and premeditation.” On May 13, 2009, the jury concluded that the government had sufficiently proven these three aggravating factors. That same day, the district court began the selection phase of Ebron’s trial. In support of its position that death was the appropriate sentence for Ebron, the government submitted two nonstatutory aggravating factors to the jury: (1) that “Ebron’s motive for the murder of Keith Barnes was Barnes’ past cooperation and testimony in the prosecution of Barnes’ co-defendants”; and (2) that “Ebron pose[d] a continuing danger to the lives and safety of others while incarcerated because it is likely that he will commit criminal acts of violence in the future.” To substantiate these factors, the government presented a number of witnesses. Two warrant brief mention at this point. First, the government had Detective Lorren Leadmon testify regarding Ebron’s first murder conviction. Second, the government presented the testimony of Peter Zeidenberg, the attorney who prosecuted Barnes for the crime that placed him in prison. While on the witness stand, Zeidenberg stated that Barnes cooperated with officials by testifying against his codefendants, including Carpenter. On May 14, 2009, five family members testified on Ebron’s behalf. Three of his aunts testified that Ebron was a normal, happy kid until he started running into trouble. Ebron’s younger brother also served as a witness and testified that Ebron had a positive impact on his life. Ebron’s stepmother also took the witness stand and stated that Ebron’s environment had a negative impact on him. Along with these family members, Ebron also presented psychological testimony and testimony from Jim Aiken, an expert whose opinion supported Ebron’s position that he would not pose a future danger in prison. In its rebuttal, the government had two individuals, including a witness named Greg Hershberger, testify in an attempt to counter Ebron’s contention that he would not pose a future danger in prison. On May 18, 2009, the jury concluded that the death penalty was the appropriate sentence for Ebron’s conviction on Count I of the indictment. The following month, the district court held a sentencing hearing on Count II. Based on a total offense level of 48 and a criminal history level of 3, the district court sentenced Ebron to a life sentence. D. In October 2009, Ebron filed a motion for a new trial in which he presented three grounds for relief. First, Ebron argued that, based on the information it had before it at trial, the district court’s decision to dismiss Johnson rather than declare a mistrial “violated his Sixth Amendment right to a unanimous verdict and his Fifth Amendment right to due process.” Second, he contended that a post-trial affidavit submitted by Johnson made “clear that Johnson believed, and told other jurors, that the Government had not proved Ebron’s guilt.” According to Ebron, this affidavit supported his position that Johnson was improperly removed from the jury. Third, Ebron argued that newly discovered statements made by Bacote were relevant and material to the central issues at trial and, given their content, would likely produce an acquittal on retrial. On January 28, 2010, the district court issued a written decision in which it rejected Ebron’s arguments and denied his motion for a new trial. This is an appeal from his convictions and death sentence. A related appeal regarding the denial of his motion for a new trial has been consolidated with this case. II. On appeal, Ebron has raised a number of issues challenging his convictions and death sentence. These issues can be organized in five general categories: (1) errors surrounding Johnson’s dismissal; (2) evidentiary errors at the guilt/innocence phase; (3) prosecutorial misconduct throughout the trial; (4) sentencing errors; and (5) post-trial error. We will address each category separately. A. The first category of issues raised by Ebron involves alleged errors surrounding Johnson’s dismissal. In his brief, Ebron contends that the district court committed the following four errors in its handling of the Johnson episode: (1) individually interviewing jurors after it questioned the foreperson; (2) dismissing Johnson from the jury; (8) denying his motions for a mistrial; and (4) failing to rehabilitate the reconstituted jury after Johnson’s dismissal. When taken together, Ebron maintains that these supposed errors warrant the reversal of his convictions. We address each contention in turn. 1. Ebron contends that the district court erred in interviewing jurors because the information it used in deciding to conduct these interviews—namely, the foreperson’s statements in his interview—showed that the jury disagreed about the merits of the case and witness credibility. Ebron asserts that because the district court did not have unambiguous evidence that Johnson was refusing to apply the law as instructed, it should have refrained from interviewing jurors. We review a district court’s response to juror misconduct for abuse of discretion. See United States v. Edwards, 803 F.3d 606, 634 (5th Cir.2002). “A trial court abuses its discretion when its ruling is based on an erroneous view of the law or a clearly erroneous assessment of the evidence.” United States v. Yanez Sosa, 513 F.3d 194, 200 (5th Cir.2008) (internal citations omitted). There are two competing interests that are implicated in a judge’s decision to investigate allegations of juror misconduct during deliberations. On one hand, it is recognized that the secrecy of deliberations is essential to the success of the jury system. “It is well understood, for example, that disclosure of the substance of deliberations may undermine public confidence in the jury system.” United States v. Thomas, 116 F.3d 606, 618 (2d Cir.1997) (citation omitted). Preserving the secrecy of jury deliberations “requires not only a vigilant watch against external threats to juror secrecy, but also strict limitations on intrusions from those who participate in the trial process itself, including counsel and the presiding judge.” Id. at 620. Thus, “[a] court must limit its own inquiries of jurors once deliberations have begun.” Id. On the other hand, juror compliance with instructions, along with fidelity to their oath, is important in preserving the sanctity of jury verdicts. While the institutional interest in the secrecy of juror deliberations is important, district courts also have a duty, and the concomitant authority, to ensure that jurors are obeying instructions and adhering to their oath. Balancing these two interests is a challenge a district court must undertake when faced with allegations of juror misconduct during deliberations. “[A] district court should be more cautious in investigating juror misconduct during deliberations than during trial, and should be exceedingly careful to avoid any disclosure of the content of deliberations.” United States v. Boone, 458 F.3d 321, 329 (3d Cir.2006). While exercising due caution, a district court may conduct an investigation in situations where it is presented with substantial evidence of jury misconduct. See id. (holding that “where substantial evidence of jury misconduct—including credible allegations of jury nullification or of a refusal to deliberate—arises during deliberations, a district court may, within its sound discretion, investigate the allegations”) (citations omitted). Such an investigation may be conducted via careful juror questioning or any other appropriate means. Id. (citations omitted). In adopt-Balancing these two interests is a challenge a district court must undertake when faced with allegations of juror misconduct during deliberations. “[A] district court should be more cautious in investigating juror misconduct during deliberations than during trial, and should be exceedingly careful to avoid any disclosure of the content of deliberations.” United States v. Boone, 458 F.3d 321, 329 (3d Cir.2006). While exercising due caution, a district court may conduct an investigation in situations where it is presented with substantial evidence of jury misconduct. See id. (holding that “where substantial evidence of jury misconduct—including credible allegations of jury nullification or of a refusal to deliberate—arises during deliberations, a district court may, within its sound discretion, investigate the allegations”) (citations omitted). Such an investigation may be conducted via careful juror questioning or any other appropriate means. Id. (citations omitted). In adopt- Here, the district court did not abuse its discretion in interviewing jurors in order to investigate allegations of juror misconduct. In his interview, the foreperson clearly indicated his belief that there was a juror who was refusing to follow the court’s instructions. Based on its response to his statement, it appears as if the district court found the foreperson credible. This credibility determination is entitled to deference. See Boone, 458 F.3d at 329. Given the clear and credible nature of the foreperson’s allegations, the district court had a sufficient basis for initiating an investigation to uncover whether a juror was in fact refusing to follow instructions. See id. at 329-30 (holding that credible allegations of misconduct can provide a basis for investigating allegations). Accordingly, the district court’s decision to conduct an investigation into juror misconduct was not an abuse of its discretion. 2. In addition, Ebron argues that the district court erred in dismissing Johnson. In his brief, he concedes that even after deliberations have begun, a juror may be dismissed for good cause. But he contends that when the nature of any alleged misconduct prompts a district court to inquire into the juror’s “thought processes,” dismissing a juror is improper unless, after inquiry, there is “no possibility” that the juror’s problem stems from her view of the sufficiency of the evidence. Ebron concludes that, since this possibility did exist in his case, the district court’s dismissal of Johnson was improper. “District courts have discretion to dismiss jurors for just cause.” Edwards, 303 F.3d at 631. “A district court abuses its discretion only when its ruling is based on an erroneous view of the law or on a clearly erroneous assessment of the evidence.” Id. (internal quotation marks and citation omitted). Moreover, “[u]nless the court’s removal of the juror has prejudiced the defendant, we will not disturb the court’s decision.” United States v. Virgen-Moreno, 265 F.3d 276, 288 (5th Cir.2001) (citing United States v. Leahy, 82 F.3d 624, 628 (5th Cir.1996)). And prejudice will be found only “if the juror was discharged without factual support or for a legally irrelevant reason.” Id. (citation and quotation marks omitted). “‘[U]nder the clearly erroneous standard, we may not reverse the district court’s findings of fact unless the review of the relevant evidence leaves us with the definite and firm conviction that a mistake has been committed.’ ” Edwards, 303 F.3d at 631 (quoting Broussard v. United States, 989 F.2d 171, 178 (5th Cir.1993)). “A factual finding is not clearly erroneous as long as it is plausible in light of the record as a whole.” United States v. Jacquinot, 258 F.3d 423, 427 (5th Cir.2001) (citation omitted). Even after deliberations have begun, a juror may be dismissed for “good cause.” Fed.R.Crim.P. 23(b)(2)(B); Edwards, 303 F.3d at 631. A juror’s inability to follow instructions is a legally valid basis for dismissal. Edwards, 303 F.3d at 631 (citing United States v. Vega, 72 F.3d 507, 512 (7th Cir.1995)). Similarly, a lack of candor can also serve as the basis for dismissing a juror. Id. (citing United States v. Fryar, 867 F.2d 850, 853 (5th Cir.1989)). In his brief, Ebron seeks to shift the applicable legal framework from the “good cause” standard to the “no possibility” rule that has been recognized in various circuits. To support his position, he relies heavily upon the Second Circuit’s decision in Thomas, the D.C. Circuit’s decision in United States v. Brown, 823 F.2d 591 (D.C.Cir.1987), and the Ninth Circuit’s decision in United States v. Symington, 195 F.3d 1080 (9th Cir.1999). According to Ebron, these decisions support the proposition that “when the nature of the alleged misconduct prompts a district court to inquire ‘into the juror’s thought processes’ ... dismissing a juror is improper, unless, after inquiry, ‘there is no possibility that the juror’s problem stems from [her] view of the sufficiency of the evidence.” This reading of Brown, Thomas, and Symington, however, is inconsistent with our interpretation of these cases. In Edwards, we read this trio of cases as standing “for the limited proposition that a court may not dismiss a juror based upon its conclusion that the juror is failing to participate in the deliberative process in accordance with the law unless there is no possibility that the juror’s problem stems from his view of the sufficiency of the evidence.” 303 F.3d at 633. In affirming the district court’s dismissal of a juror for lack of candor and an inability to follow instructions, this court interpreted the reasoning in Brown, Thomas, and Symington as extending “only to those dismissals where the juror’s conduct cannot be evaluated without delving into the reasons underlying the jurors’ views of the case, i.e., where the deliberative process has been implicated.” Id. Under Edwards’s reading of Brown, Thomas, and Symington, the “no possibility” rule is triggered only when the district court dismisses a juror based on its “conclusion that the juror is failing to participate in the deliberative process in accordance with the law.” Id. Here, the district court’s dismissal of Johnson was not based solely on Johnson’s failure to properly participate in the deliberative process. Rather, it removed Johnson from the jury for three reasons: (1) bias based on “personal feelings”; (2) her failure to abide by the juror’s oath in introducing “extrinsic evidence” during jury deliberations; and (3) lack of candor under oath. Given that the latter two reasons are independent and do not implicate the deliberative process, the “no possibility” rule applied in Brown, Thomas, and Symington is inapplicable in this case. Had the district court dismissed Johnson based on bias alone, we would have been faced with deciding whether to formally incorporate some variation of the “no possibility” rule into our jurisprudence. But here, where the district court provided two independent reasons for dismissal that (1) do not involve a “fail[ure] to participate in the deliberative process in accordance with the law”; and (2) are plausible in light of the record as a whole and are thus not clearly erroneous, such a jurisprudential step is unnecessary. Instead, our resolution of this issue can be based solely on an application of Rule 2B’s good cause standard. Under this standard, the district court did not abuse its discretion in dismissing Johnson. The two aforementioned reasons — lack of candor and a failure to abide by instructions — are legally valid grounds for dismissing a juror. Edwards, 303 F.3d at 631. Our decision in Edwards supports this conclusion. In that case, we affirmed the dismissal of a juror based on a lack of candor and a failure to abide by instructions. Id. After setting forth our understanding of the “no possibility” rule, we concluded that because dismissals on the aforementioned grounds do not implicate the deliberative process, they do not trigger the rule set forth in Brown, Thomas, and Symington. Here, the district court dismissed Johnson on similar grounds. In light of the similarities between the basis for dismissal in Edwards and the grounds provided by the district court in this case, we conclude that Johnson’s dismissal was consistent with this circuit’s case law. The district court therefore did not abuse its discretion in dismissing Johnson. 3. Ebron asserts that after its interview with the foreperson, the district court was aware that the jury was deadlocked. Based on this interview and the notes submitted by the jury, Ebron maintains that the jury was clearly deadlocked. He contends that because a deadlocked jury presents the classic basis for a mistrial, the district court should have granted his motion for a mistrial. Relatedly, he argues that the district court should have granted the motion for a mistrial he made after the district court interviewed the remaining jurors. According to Ebron, a mistrial should have been granted not only because of the problems the jury was facing, but also because of the alleged taint that Johnson’s removal left on a reconstituted jury. The decision whether to grant a mistrial is reserved to the broad discretion of the trial judge. Renico v. Lett, — U.S. -, 130 S.Ct. 1855, 1863, 176 L.Ed.2d 678 (2010). A district court’s decision to deny a mistrial is reviewed for abuse of discretion. United States v. Mitchell, 166 F.3d 748, 751 (5th Cir.1999). “[T]rial judges may declare a mistrial “whenever, in their opinion, taking all the circumstances into consideration, there is a manifest necessity1 for doing so.” Renico, 130 S.Ct. at 1863 (quoting United States v. Perez, 22 U.S. (9 Wheat.) 579, 580, 6 L.Ed. 165 (1824)). “The decision to declare a mistrial is left to the ‘sound discretion’ of the judge, but ‘the power ought to be used with the greatest caution, under urgent circumstances, and for very plain and obvious cases.’ ” Id. Since Perez, the Supreme Court has clarified that the “manifest necessity” standard cannot be interpreted literally, and that a mistrial is appropriate when there is a high degree of necessity. Id. In this case, the district court did not abuse its discretion in denying the aforementioned motions for a mistrial. First, with respect to the denial after the foreperson’s interview, we do not conclude that the district court abused its discretion in deciding that a mistrial was not a manifest necessity. Given the information the foreperson provided regarding one juror’s alleged failure to follow instructions, it was reasonable for the district court to investigate this allegation. Granted, in light of the information it had received regarding the jury being deadlocked, the district court could have potentially declared a mistrial. See Renico, 130 S.Ct. at 1863 (noting that a mistrial premised upon the trial judge’s belief that the jury is unable to reach a verdict has long been considered the classic basis for a proper mistrial). But given the allegations regarding juror misconduct, it also had the discretion to conduct an investigation into those allegations. The district court’s decision to choose the latter course of action is not an abuse of its broad discretion. Contrary to what Ebron suggests, the fact that the district court had information suggesting that the jury was deadlocked does not mandate a mistrial. Such an argument relies upon an incorrect and rigid understanding of what is required to support a mistrial. See id. (“We have expressly declined to require the ‘mechanical application’ of any ‘rigid formula’ when trial judges decide whether jury deadlock warrants a mistrial.”). Second, with respect to the motion presented after juror interviews, we do not conclude that the district court abused its discretion in not declaring a mistrial. When presented with this motion, the district court had the option of making one of two discretionary decisions: (1) it could have declared a mistrial based on the problems the jury was having and the introduction of extrinsic information into deliberations; or (2) it could have dismissed Johnson and replaced her with an alternate. Given the availability of the latter option, the district court was not faced with “urgent circumstances” which would have made a mistrial a manifest necessity. In its judgment, the district court believed that the second option was acceptable. Based on the totality of the record, the approach taken by the district court was not an abuse of its broad discretion. In sum, we determine that the district court did not abuse its discretion in refusing to grant Ebron’s motions for a mistrial. 4. Along with his first three challenges in this category, Ebron also contends that the instructions provided by the district court after Johnson’s dismissal were inadequate. According to him, more instructions were required. Specifically, he notes that the district court failed to do the following: (1) “advise the jury to disregard the so-called ‘extrinsic’ evidence that was the purported reason for Johnson’s dismissal”; (2) “tell the jurors to disregard whatever had gone on during their prior deliberations”; and (3) inform “jurors that they were not to infer that the [district court] held any views regarding the proper verdict to be rendered.” The district court erred, Ebron concludes, in not providing these instructions. In addition, he argues that the district court erred by failing to interview jurors individually after Johnson’s removal “to attempt to ensure that the jury was rehabilitated.” Ebron did not object to any of these alleged deficiencies at trial. “Where a party fails to offer a timely objection to jury instructions, claims of error are reviewed for plain error.” United States v. Diaz, 637 F.3d 592, 601 (5th Cir.2011). Under the plain error standard of review, “[a]n appellate court may not correct an error the defendant failed to raise in the district court unless there is ‘(1) error, (2) that is plain, and (3) that affects substantial rights.’ ” United States v. Mares, 402 F.3d 511, 520 (5th Cir.2005) (quoting United States v. Cotton, 535 U.S. 625, 631, 122 S.Ct. 1781, 152 L.Ed.2d 860 (2002)). “ ‘If all three conditions are met an appellate court may then exercise its discretion to notice a forfeited error but only if (4) the error seriously affects the fairness, integrity, or public reputation of judicial proceedings.’ ” Id. (quoting Cotton, 535 U.S. at 631, 122 S.Ct. 1781). This standard of review “requires considerable deference to the district court.” United States v. Peltier, 505 F.3d 389, 391 (5th Cir.2007). Under the Federal Rules of Criminal Procedure, once an “alternate replaces a juror after deliberations have begun, the court must instruct the jury to begin its deliberations anew.” Fed.R.Crim.P. 24(c)(3). The record reflects that the district court did exactly what Rule 24(c)(3) requires when it replaced Johnson with an alternate. On the morning of May 11, 2009, the reconstituted jury began its deliberations. Before the jury started deliberating, the district court provided the following instruction: As you notice, a new juror has been substituted. You’re not to discuss or speculate as to the cause for the change in the jury complement. You must, however, begin your deliberations anew, as the new juror has not had the benefit of your previous discussions and examination of the evidence and you have not had the benefit of his views. In his brief, Ebron does not point to any binding legal precedent that supports his assertion that the district court erred in failing to provide a more extensive set of instructions. His argument regarding rehabilitative interviews of jurors is similarly unsupported. Because the district court did exactly what Rule 24(c)(3) requires, it did not err. Accordingly, Ebron’s arguments regarding the adequacy of the district court’s treatment of the reconstituted jury fail to provide a basis for unsettling his convictions. 5. Ebron argues that, when viewed cumulatively, the “errors involving the jurors’ deadlock — the district court’s refusal to grant a mistrial, the removal of a holdout juror, and the inadequate rehabilitation of the new jury — combined to produce a coerced verdict.” In making this argument, he appears to invoke the cumulative error doctrine. We are unpersuaded by his position. “A fair trial in a fair tribunal is a basic requirement of due process.” In re Murchison, 349 U.S. 133, 136, 75 S.Ct. 623, 99 L.Ed. 942 (1955). Under the cumulative error doctrine, “an aggregation of non-reversible errors (i.e., plain errors failing to necessitate reversal and harmless errors) can yield a denial of the constitutional right to a fair trial, which calls for reversal.” United States v. Munoz, 150 F.3d 401, 418 (5th Cir.1998) (citations omitted). In applying this doctrine, a court must determine whether the errors “so fatally infect the trial that they violated the trial’s fundamental fairness.” United States v. Fields, 483 F.3d 313, 362 (5th Cir.2007) (quoting United States v. Bell, 367 F.3d 452, 471 (5th Cir.2004)). In this case, the cumulative error doctrine does not apply for one simple reason: there is nothing to cumulate. The district court did not abuse its discretion in choosing to investigate and remove Johnson rather than declare a mistrial. Nor did the district court plainly err in not providing a more extensive set of instructions to the reconstituted jury or failing to conduct rehabilitative juror interviews. Accordingly, the cumulative error doctrine cannot be used to undermine Ebron’s convictions. B. The second category of issues raised by Ebron addresses various alleged evidentiary errors that he claims tainted the guilt/innoeence phase of his trial. According to Ebron, the district court abused its discretion in admitting various forms of extrinsic evidence, hearsay, and expert testimony. In addition, he claims that the district court plainly erred in admitting other forms of hearsay and expert/lay testimony. We address each contention in turn. 1. At trial, the government presented testimony regarding three fights Ebron participated in while housed at USP-Atlanta. First, the government presented the testimony of Tim Zuppinger, a food administrator at USP-Atlanta. In his testimony, Zuppinger stated that in May 2003, Ebron and Carpenter assaulted another inmate, Joseph Brown, in the cafeteria. According to Zuppinger, when the fight was broken up, Carpenter yelled, “That’s how we handle snitches, bitch!” Second, the government had Leander White, a corrections officer at USP-Atlanta, testify. According to White, Ebron and Carpenter attacked Brown a second time when the three men were placed in a holding tank. After Carpenter was subdued, White asked Carpenter why he attacked Brown. In response, Carpenter stated, “Man, that dude ain’t nothing but a snitch.” After Carpenter made this statement, Ebron allegedly stated, ‘We already know that dude is a snitch.” Third, the district court admitted the testimony of Steven Perry, another USP-Atlanta worker, who stated that on the morning of November 10, 2003, Ebron and Carpenter attacked an inmate whose surname is also Perry. Ebron objected to the admission of these witnesses’ testimony at trial. On appeal, Ebron recognizes that Federal Rule of Evidence 404(b) allows for the introduction of prior bad acts for the purpose of proving motive or intent, but argues that the testimony regarding these three incidents was irrelevant for both purposes. Alternatively, he contends that even if this “evidence was marginally probative of intent or motive, reversal is required because any probative value it may have had was far outweighed by its unfair prejudice.” A district court’s admission of extrinsic evidence over a Rule 404(b) objection is reviewed under a heightened abuse of discretion standard. United States v. Alarcon, 261 F.3d 416, 424 (5th Cir.2001). Under this standard of review, erroneous admissions under Rule 404(b) are subject to a harmless error inquiry. United States v. McCall, 553 F.3d 821, 827 (5th Cir.2008) (citation omitted). The government has the burden of establishing harmlessness beyond a reasonable doubt. Id. (citation omitted). Rule 404(b) provides that “evidence 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). In criminal cases, however, this “evidence may be admissible for another purpose, such as proving motive, opportunity, intent, preparation, plan, knowledge, identity, absence of mistake, or lack of accident.” Id. at (b)(2). It is unnecessary that the extrinsic evidence fit neatly under one of the exceptions listed in Rule 404(b), as this list is not exhaustive. See Wright & Graham, Federal Practice and Procedure: Evidence § 5248 (explaining that “[t]he list of ‘exceptions’ in Rule 404(b) is really no more than a set of examples of instances in which the use of the evidence does not offend the general rule of exclusion”). “[T]he general rule of exclusion in Rule 404(b) only excludes evidence of other crimes when offered to prove the conduct of a person by resort to an inference as to his character.” Id. In United States v. Beechum, we interpreted Rule 404(b) and announced the following two-step test for determining the admissibility of extrinsic evidence: First, it must be determined that the extrinsic offense evidence is relevant to an issue other than the defendant’s character. Second, the evidence must possess probative value that is not substantially outweighed by its undue prejudice[.] 582 F.2d 898, 911 (5th Cir.1978). Here, the first portion of the Beechum analysis has been satisfied. The three USP-Atlanta incidents involving Carpenter and Ebron are relevant for purposes of establishing motive. Specifically, this evidence demonstrates a relationship between Carpenter and Ebron, which, in turn, is relevant to the issue of whether Ebron had a motive to kill Barnes, the individual who helped put Carpenter behind bars. Because these, prior incidents are relevant to an issue other than Ebron’s character, the challenged testimony satisfies the first portion of the Beechum analysis. The second portion of the Beechum analysis has also been satisfied. Under this portion of the analysis, we must consider whether the extrinsic evidence possesses a probative value that is not substantially outweighed by its undue prejudice. In terms of probative value, we conclude that the challenged evidence is probative in establishing a motive for Ebron’s actions. This probative value, we also conclude, is not substantially outweighed by any undue prejudice. In its instructions, the district court noted that this testimony could be used for “limited purposes,” namely, “to determine whether [Ebron] had the state of mind, motive, or intent necessary to commit the crime charged in the indictment.” A similar instruction was provided at the end of the guilt/innocence phase of the trial. In the past, this court has indicated that the prejudicial effect of Rule 404(b) testimony may be minimized by a proper jury instruction. See United States v. Taylor, 210 F.3d 311, 318 (5th Cir.2000); McCall, 553 F.3d at 829 (“Any prejudice was certainly mitigated, even if not eliminated, by the district court’s limiting instruction given contemporaneously with the admission of the evidence, which limiting instruction the district court repeated during the jury charge.”). Because we must presume that the jury followed the district court’s instructions, see Zafiro v. United States, 506 U.S. 534, 540, 113 S.Ct. 933, 122 L.Ed.2d 317 (1993), we determine that any possible prejudice Ebron suffered as a result of the inclusion of the challenged testimony was mitigated to the point where it did not substantially outweigh its probative value. Accordingly, we conclude that the second portion of the Beechum analysis has been satisfied. The district court therefore did not abuse its discretion in admitting the testimony provided by the government’s Rule 404(b) witnesses. 2. Ebron also argues that the district court erred in admitting certain portions of Lamont Bailey’s testimony. In his testimony, Bailey stated that Mosley told him that Mosley and “Akh went in [Barnes’s cell] and put in the work,” and that Mosley “stabbed [Barnes] so many times that they had to take breaks.” At trial, the district court admitted this testimony, over Ebron’s objection, as a statement against penal interest. On appeal, Ebron argues that “[w]hile the statement implicating Mosley himself in the stabbing may have qualified as a statement against penal interest, the statement about ‘Akh,’ who the Government argued was Ebron, did not and should have been excluded.” “Review of a trial court’s evidentiary rulings is for abuse of discretion, subject to harmless error review.” United States v. Jackson, 636 F.3d 687, 692 (5th Cir.2011) (citation omitted). “A trial court abuses its discretion when its ruling is based on an erroneous view of the law or a clearly erroneous assessment of the evidence.” Yanez Sosa, 513 F.3d at 200. Federal Rule of Evidence 804(b)(3) creates a limited exception to the hearsay rule for statements against the declarant’s penal interest. To be admissible under Rule 804(b)(3), such a declaration must meet the following three-part test: (1) The declarant must be unavailable; (2) The statement must so far tend to subject the declarant to criminal liability that a reasonable person in his position would not have made the statement unless he believed it to be true; and (3) The statement must be corroborated by circumstances clearly indicating its trustworthiness. United States v. Dean, 59 F.3d 1479, 1492 (5th Cir.1995) (quotation marks and citation omitted). “We will uphold a district court’s determination as to the trustworthiness of an out-of-court statement unless it is clearly erroneous.” Id. (citation omitted). In this case, the parties do not dispute that Mosley’s statement implicating himself in the murder is a statement against penal interest. What they do dispute is the admissibility of the statement’s reference to “Akh.” According to Ebron, the Supreme Court’s decision in Williamson v. United States, 512 U.S. 594, 114 S.Ct. 2431, 129 L.Ed.2d 476 (1994), stands for the proposition that the “against-penal-interest exception to the hearsay rule does not allow admission of non-self-inculpatory statements, even if they are made within a broader narrative that is generally self-inculpatory.” From this proposition, Ebron argues that the non-self-inculpatory reference to Akh in Mosley’ statement to Bailey is not admissible under Rule 804(b)(3). Ebron overreads Williamson. In Williamson, the Supreme Court issued a fractured opinion in which it indeed held that “the most faithful reading of Rule 804(b)(3) is that it does not allow admission of non-self-inculpatory statements, even if they are made within a broader narrative that is generally self-inculpatory.” 512 U.S. at 600-01, 114 S.Ct. 2431. Notably, however, the statement at issue in Williamson was made to authorities after the declarant was arrested. See id. at 596, 114 S.Ct. 2431. In contrast, Mosley’s statement was made to a fellow inmate. This distinction, we conclude, is consequential. Unlike the situation where a declarant implicates himself and the defendant in a statement made to officials, a statement made outside a custodial context does not provide the same set of incentives that create the risk of an unreliable statement. Given this important distinction, we are convinced that Williamson, despite some of its broad language, does not govern the admissibility of Bailey’s testimony. In the wake of the Supreme Court’s divided opinions in Williamson and Lilly v. Virginia, 527 U.S. 116, 119 S.Ct. 1887, 144 L.Ed.2d 117 (1999), this area of law appears to be fraught with uncertainty.. See Mueller at § 8.75 (“In the uncertainty left by the divided opinions in Williamson and Lilly, courts sometimes find that [Rule 804(b)(3) ] does reach third-party statements mentioning the defendant.”). This uncertainty is heightened in this case because, unlike the statements at issue in Williamson and Lilly, Mosley’s statement was not made during custodial questioning. Given this uncertainty, the district court did not abuse its discretion in admitting the challenged portions of Bailey’s testimony. See Yanez Sosa, 513 F.3d at 200 (holding that a trial court abuses its discretion when its ruling is based on an erroneous view of the law). 3. Along with the two aforementioned evidentiary challenges, Ebron also contends that the district court, over his objection, improperly admitted James Carpenter’s letters. As stated earlier, these letters contained various statements revealing Carpenter’s negative feelings towards Barnes and a taste for revenge. We review the admission of this evidence for abuse of discretion, subject to harmless error review. See Jackson, 636 F.3d at 692. Rule 804(b)(3) of the Federal Rules of Evidence creates a limited exception to the hearsay rule. As stated above, to be admissible under Rule 804(b)(3), a declaration must meet the following three-part test: (1) the declarant must be unavailable; (2) the statement must so far tend to subject the declarant to criminal liability that a reasonable person in his position would not have made the statement unless he believed it to be true; and (3) the statement must be corroborated by circumstances clearly indicating its trustworthiness. Dean, 59 F.3d at 1492 (citation omitted). The parties do not dispute the first and third parts of the test set forth in Dean. What they do dispute is whether Carpenter’s letters tended to subject him to criminal liability. This circuit has not read Rule 804(b)(3) to be limited to direct confessions of guilt. United, States v. Thomas, 571 F.2d 285, 288 (5th Cir.1978). “Rather, by referring to statements that ‘tend’ to subject the declarant to criminal liability, the Rule encompasses disserving statements by a declarant that would have probative value in a trial against the declarant.” Id. As part of this analysis, we must consider whether the statements made in Carpenter’s letters “would not have been made by a reasonable man in his position ... unless he believed [them] to be true.” Id. at 289 (internal quotation marks omitted). The letters at issue were collected by D.C. detectives prior to Carpenter’s 1998 murder trial. In these letters, Carpenter makes statements that could be interpreted as implicating himself in criminal activity and indicating that he was upset that others were providing information to authorities. While the exact date these letters were written is unclear, it is clear that they were drafted before Carpenter’s murder trial. It is also evident that a reasonable person awaiting trial would not make these types of statements unless they were true. Though by no means conclusive of guilt or wrongdoing, these letters could have been harmful to Carpenter if presented at his trial. As such, although they are not direct confessions of guilt, they can be considered statements against penal interest. The district court therefore did not abuse its discretion in admitting Carpenter’s letters. 4. In his fourth genera