concurring in' part and dissenting in part,
I concur in Parts II, III, and IV of the court’s decision. However, I respectfully dissent from Part I because, in my view, the district court did not err in finding that Tucker had failed to raise reasonable grounds for a more searching post-trial hearing than that conducted. Indeed, under clearly established law, the pleadings and papers advanced by Tucker required no hearing whatsoever. Thus, the court violates the applicable “abuse of discretion” standard of review with this remand.
The district court determined that Tucker failed to submit “any specific evidence demonstrating any impropriety on the part of juror Johnson, or the entire panel, but has submitted rank hearsay.” Tr. of Hr’g at 3 (August 1, 1996). The district court characterized the Tucker argument as “based on speculation and conjecture.” Id. Everything before the court, on appeal, supports the district court’s conclusion. The court, in conducting its erroneous analysis, has converted conclusory allegations by Tucker into findings of fact at odds with evidentiary rulings and credibility determinations reached by the district court, the tribunal with sole discretion to resolve these issues. See Smith v. Phillips, 455 U.S. 209, 222, 102 S.Ct. 940, 948-49, 71 L.Ed.2d 78 (1982) (O’Connor, J., concurring).
Tucker presents a concoction of speculation and conjecture based on the purported state of mind of one Robert “Say” McIntosh, juror Johnson’s uncle by marriage whom she did not know, and of Charles Hayes, Johnson’s fiancé turned husband, a person that she apparently had little if anything to do with at times relevant to most of Tucker’s allegations. The issue is, of course, the state of mind of Johnson and no one else. Because Tucker advanced only speculative allegations with regard to Johnson’s state of mind, the court’s remand order requires it to make unsupported factual and legal leaps of unprecedented proportions.
The court correctly observes that Tucker’s motion—-alleging that his Sixth Amendment right to an impartial jury requires a new trial—raises two separate theories. First, Tucker alleges that Johnson harbored a bias against him and that she failed to answer honestly certain questions during voir dire that would have revealed her bias. . Next, Tucker contends that Johnson received improper communications during the trial. The district court refused to conduct a post-trial hearing into the juror bias claim and conducted a limited inquiry into the improper communications allegation. Because an appellate court is generally not the proper tribunal to vacate a verdict and order a new trial, see McDonough Power Equip., Inc. v. Greenwood, 464 U.S. 548, 551 n. 3, 104 S.Ct. 845, 848 n. 3, 78 L.Ed.2d 663 (1984), we must only decide whether the district court erred in not- conducting a more extensiye investigation into Tucker’s allegations. I find no error in that regard.
The mere fact that post-verdict allegations of juror bias or misconduct are made does not automatically create a right to a héaring. See also McDonough, 464 U.S. at 556, 104 S.Ct. at 850 (Blackmun, J., concurring) (stating that the decision to conduct a post-trial hearing to determine juror bias remains within the “trial court’s option”); United States v. Moses, 15 F.3d 774, 778 (8th Cir.1994) (same). Clearly, our limited judicial resources prevent us from ferreting out every instance of alleged bias or otherwise guaranteeing perfect trials. See Lutwak v. United States, 344 U.S. 604, 619, 73 S.Ct. 481, 490, 97 L.Ed. 593 (1952). Needless posttrial interviews of jurors could result in juror harassment and cause grave danger to the effectivéness of our jury system. See Tanner v. United States, 483 U.S. 107, 120, 107 S.Ct. 2739, 2747, 97 L.Ed.2d 90 (1987) *1038(observing that the jury system would likely not survive efforts at perfection).
Thus, before ordering a post-trial hearing, the district court must determine whether an allegation of concealed juror bias or misconduct even warrants further investigation. See United States v. Caldwell, 83 F.3d 954, 957 (8th Cir.1996). We give broad deference to the district court in this determination because it is better positioned to consider the relevance and materiality of supporting facts and the possibility of bias. Id. The district court’s duty to investigate is primarily determined by the nature of the losing litigant’s allegations supporting the claim of bias or misconduct and the severity of the allegations. See United States v. Caldwell, 776 F.2d 989, 998 (11th Cir.1985). In the absence of substantiated, non-speculative allegations of material, pre-existing bias or misconduct, we need not permit convicted defendants “to waste the time of a district judge or inconvenience jurors merely to conduct a fishing expedition.” United States v. Moten, 582 F.2d 654, 667 (2d Cir.1978); see also Moses, 15 F.3d at 778 (holding that a convicted defendant is not entitled to a post-trial hearing on the issue of juror misconduct based on a vague and uncertain affidavit of a juror that “never explains the basis of his suspicion”). I disagree with the court’s conclusions that Tucker’s allegations provide reasonable grounds for a post-trial hearing into the allegations of concealed juror bias and that Tucker’s allegation of improper communications warrants any more searching a hearing than that conducted. Most important, however, I believe that the district court acted within its discretion.
A. Juror Bias
In support of his theory of concealed juror bias, Tucker relies upon the fact that, during his trial, Johnson married Charles Hayes, a former prisoner who had been denied executive clemency by Tucker. Tucker also alleges that Hayes is the nephew of a local activist, Say McIntosh, who frequently spoke out against Tucker before and during the criminal trial. Tucker argues that Johnson improperly failed to reveal these relationships during voir dire questioning, preventing him from discovering her alleged bias.
On a written jury questionnaire, which she answered prior to her courthouse marriage, Johnson indicated that she was single (as opposed to married, divorced, widowed or separated as set forth in the inquiry) and responded “n/a” (not applicable) to family information inquiries concerning a spouse.14 Johnson was also asked, “Have you or any member of your family ever been charged with a crime?” She answered, yes. Next, the questionnaire stated, “If yes, what was the charge?” Johnson answered, “Drug [cjonviction.” The questionnaire then asked, “How did the case end?” Johnson answered, “guilty (serving 4 years).” Tucker contends that Johnson’s affirmative answer referred to her brother-in-law and his drug conviction and not to Charles Hayes. This is probably a correct contention because Johnson’s sister wás, at the time of trial, married to Hayes’s brother, Brian, who was apparently then serving a four-year sentence on a drug conviction. Charles Hayes, on the other hand, had been released from prison in April of 1993, which, according to the record, occurred prior to commencement of the Johnson/Charles Hayes relationship. In any event, Tucker asked no further questions about this answer during the voir dire examination.
Johnson’s answers to the questions posed were honest, complete, and correct because “family” does not include one’s fiancé. See United States v. Rushing, 24 F.3d 243 (8th Cir.1994) (holding that “family” does not include a girlfriend’s son). The court mistakenly breathes new life into this relatively narrow question. As the record reveals, Johnson and Charles Hayes were merely *1039engaged and had not even set a wedding date at the time of voir dire. We have previously rejected similarly broad post-trial interpretations of voir dire questions. See id.; United States v. Wright, 119 F.3d 630, 636 (8th Cir.1997); United States v. Williams, 77 F.3d 1098, 1100-01, cert. denied, — U.S. -, 117 S.Ct. 392, 136 L.Ed.2d 308 (1996); Bolin v. Black, 875 F.2d 1343, 1350 (8th Cir.1989). Here, Johnson did not deliberately conceal any bias or even answer incorrectly—she merely answered the questions posed. Consequently, the district court reasonably concluded that no further inquiry into the questionnaire was warranted.
Furthermore, Tucker waived any bias claim based on Johnson’s questionnaire answer. If Johnson had interpreted “family” to include her flaneé, her answer would have been substantially similar to that given. Thus, if Tucker was really interested in the subject, he had an obligation to ask more probing questions during voir dire about her family member’s drug conviction. See United States v. Humphreys, 982 F.2d 254, 261 (8th Cir.1992) (holding that a defendant may waive post-trial claim of juror bias if the defendant does not “diligently and timely discover the relevant information”). Tucker failed to do so, possibly in a gamble that Johnson would be more sympathetic to the defense. The court posits that the .alleged inaccuracy in Johnson’s answer to the question precludes a waiver analysis. See ante at 1029. However, as earlier noted, Johnson’s “family” member with a drug conviction was Charles Hayes’s brother, who was, at the time of voir dire, married to Johnson’s sister and in prison. Therefore, if Tucker had pursued the issue, as he should have, he would have at least discovered Johnson’s - general association with the Hayes family, regardless of the allegedly inaccurate questionnaire answer. His failure to do so waived the concealed juror bias claim.
The court also finds that Johnson’s failure to respond to general questions regarding any potential sources of bias entitles Tucker to a post-trial hearing. However, Tucker failed to support his motion for a new trial with anything remotely approaching what is required—substantiated, non-speculative allegations of material, pre-existing bias on the part of Johnson. See Moses, 15 F.3d at 778; Moten, 582 F.2d at 667. The test focuses on whether Tucker raised reasonable grounds demonstrating concealed bias on the part of Johnson, not on the part of her husband or members of her husband’s extended family. Considering the speculative and vague nature of the allegations that Tucker offered, the district court properly refused to conduct a post-trial hearing into those allegations.
The serious mistake the court makes in this regard is its apparent acceptance of Tucker’s claim that Hayes was a- part of Johnson’s family at the time of the questionnaire and voir dire. This allegation, of course, does not accurately depict their relationship. Hayes was not a member of her family at the time of voir dire and was correctly not considered a family member by Johnson. Her answers were therefore fully responsive, correct, and truthful, and they serve to establish no pre-existing bias whatsoever.
Even if we were to accept the rationale that Johnson did, or should have, considered Charles Hayes a part of her family, a proposition supported only by speculation, inference, and an overreaching search for a definition of the term “family,” Tucker has advanced no support for his allegation that Johnson was biased. See McDonough, 464 U.S. at 556, 104 S.Ct. at 850; id. (Black-mun, J., concurring) (stating that the “proper inquiry” is on the juror’s impartiality); id. at 557-58, 104 S.Ct. at 850-51 (Brennan, J., concurring) (stating that a litigant should be required to show that the juror was biased). Tucker has only raised support for the allegation that Johnson’s husband and extended family harbored -a bias against Tucker, which is, of course, irrelevant to the issue of Johnson’s partiality.
In spite of Tucker’s failure to come forth with evidence of Johnson’s alleged bias, the court validates a fishing expedition that allows Tucker to attempt to develop the kind of facts necessary to permit a post-trial inquiry in the first instance. The court commands this exploratory expedition in the face of statements under oath by Johnson, credited by the district court, that she knew nothing *1040of Charles Hayes’s or Say McIntosh’s state of mind toward Tucker. As indicated, Tucker has offered absolutely nothing that refutes Johnson’s testimony, but now wishes to attack her court-accepted credibility in an effort to overcome the factual shortcomings inherent in his assault on her purported state of mind. This approach is clearly contrary to McDonough, Moten, Humphreys, and numerous other eases from this circuit. Indeed, the court does not cite a single case in support of this result and I have found none.
B. Improper Communications Allegation
We also review for an abuse of discretion the scope of a post-trial hearing into an allegation of improper communication with a juror. See Caldwell, 83 F.3d at 957; Moten, 582 F.2d at 665-66. Here, considering the vague allegations made,by Tucker, I would find that the district court clearly acted within its discretion. Remanding this matter will only result in - another unnecessary fishing expedition and the improper harassment of Johnson.
The court makes two significant errors in its analysis: first, that Tucker’s allegation of improper communications is “supported by evidentiary materials with significant indicia of reliability;” and second, that the post-trial hearing consisted merely of “asking the juror whether [she] committed the misconduct.” Ante at 1032.
The hearsay-riddled, eonclusory affidavit of an Arkansas State Senator stating that he was told by Tommy McIntosh that Tommy had talked to Charles Hayes and that Charles had told Tommy that Charles had talked about the trial with his wife during the trial is not evidence with any “significant indicia of reliability” that is relevant to any proper inquiry in this ease. The affidavit merely states that Hayes talked about the trial “with his wife during the trial,” and it falls short of even speculating about the substance of the conversations between Hayes and Johnson. This is fatal to Tucker’s claim. The court again overemphasizes the purported animosity that Charles Hayes and his extended family have exhibited, toward Tucker without giving due consideration to whether Tucker offered any substantiated, non-speculative allegations of material improper communications.
“Erring on the side of caution,” the district court held a post-trial hearing to investigate the matter further. Tr. of Hr’g at 3. Tucker had the opportunity to examine all twelve jurors, each of whom testified that no extraneous information entered the jury room. Tucker also questioned Johnson about whether she discussed the trial with her husband while empaneled. ■ Johnson testified and emphatically denied that she improperly discussed the trial with her husband. She also testified that she had no knowledge of the activities of her husband’s uncle. The district court obviously credited Johnson’s testimony and under controlling law this court has no authority to hold that finding of fact to be erroneous.
Given this evidence, the court engages in speculation and conjecture of its own on its way to its erroneous conclusion. The court states that “[c]ontamination of a different kind [other than exposure of a juror to an extraneous fact] occurs when, rather than being exposed to a fact not in evidence, a juror is subjected to psychological pressure by an outsider trying to coopt that juror’s vote.” Ante at 1032. Of course, there is no evidence that such pressure existed. Indeed, the evidence given under oath by Johnson is flatly to the contrary. She specifically testified in response to Tucker’s questions that she only knew of Say McIntosh, and that she knew' of no communication by Say McIntosh to anyone during the trial. Tr. of Hr’g at 12. She also testified that although she knew her husband had been in prison, she knew nothing of the clemency matter which appears to have occurred well before they became closely acquainted and before this court granted habeas relief, releasing Charles Hayes from prison in 1993. See id. at 10, 11 and 12; Hayes v. Lockhart, No. 92-2979, 1993 WL 91269 (8th Cir. Mar. 31, 1993). The court simply elevates Tucker’s, speculative, unsupported allegations to the status of fact in erroneously arriving at its decision to remand this matter for further hearing.
Tucker has failed to identify the nature of the extraneous information that he suggests *1041was communicated to Johnson, but now claims that the district court erred in precluding him from examining her husband, her husband’s cousin, and the state senator who spoke to her husband’s cousin about the trial. Such a far-reaching hearing is not warranted in the absence of substantiated, non-speculative allegations of material juror misconduct. See Caldwell, 88 F.3d at 957. Tucker had his chance to present such allegations at the post-trial hearing and on his proffer of evidence before this court, but presented only allegations “based on speculation and conjecture.” Tr. of Hr’g at 3. Accordingly, I disagree with the court’s decision to remand this case to conduct a more expansive hearing into the allegation of improper communications.
Because I do not believe federal law or the Constitution requires the district courts to waste scarce judicial resources by guiding post-trial fishing expeditions into naked allegations of juror bias or misconduct, I dissent from Part I.
. These answers respond to the court’s concerns, ante at 1028, that Tucker’s counsel was not permitted to' question Johnson at the post-trial hearing on whether she considered herself a "part of a family with Hayes" at the time of voir dire. Obviously she did not because she considered herself single. She did respond that she had a child of "3 months.” If her relationships were actually unknown to him or as important as he now contends, nothing prohibited Tucker from making further inquiry at voir dire as to the identity of the father of Johnson’s child and her association with him. Tucker failed to do so.