Opinion for the Court filed by Circuit Judge SILBERMAN.
Opinion dissenting in part and concurring in part filed by Circuit Judge RANDOLPH.
SILBERMAN, Circuit Judge:
Appellants Donald Holloman and Jermaine Boney appeal their drug trafficking convictions. Both were convicted under 21 U.S.C. § 841(a) for distribution of cocaine, and one, Boney, was also convicted of possession of 12.72 grams of cocaine. Boney claims that the district court erroneously permitted an expert witness to testify as to his guilt. Holloman objects to the district court’s failure to give an identification instruction to the jury and contends that the court improperly considered for sentencing purposes the very 12.72 grams of cocaine involved in the possession charge of which he was acquitted. Both appellants assert that their Sixth Amendment right to' an impartial jury was violated because after trial it was discovered that one of the jurors was a convicted felon. We affirm on all issues except the Sixth Amendment juror bias claim. We remand for the district court to hold a hearing into actual bias.
I.
Shortly after midnight on September 12, 1989, an undercover officer of the Metropolitan Police Department, Darrell Young, approached Jeffrey Marks and sought to buy twenty dollars worth of crack cocaine. Marks asked appellant Donald A. Hollo-man, who was standing a short distance away, to “serve” Investigator Young. Hol-loman replied that he might not have enough. Marks thereupon called to appellant Jermaine Boney, who was also standing nearby, and told him to “break ... a piece off the rock.” Boney walked to a pickup truck, reached down behind the rear tire, and retrieved a plastic bag which held what Young described as a large off-white rock. Holloman then said that he had enough for the transaction and gave Investigator Young .199 grams of cocaine base of 84% purity. Young, in exchange, gave Holloman a twenty dollar bill with a prerecorded serial number.
After returning to his car, Young radioed members of his arrest team to move in and told them that Holloman was walking toward a nearby gas station. As they approached, one of the arresting officers saw Boney throw a plastic bag under the pickup truck. Another officer retrieved the bag, which contained 12.72 grams of cocaine base of 69% purity. Boney and Marks were arrested at the scene of the sale. Holloman was arrested while standing at the cashier’s window in the nearby gas station. Holloman and the cashier were the only people at the station, and the pre-marked twenty dollar bill was on the counter in front of Holloman. Young identified all three suspects at the scene of the arrest.
Marks, Holloman, and Boney were tried before a jury for distributing the .199 grams of cocaine purchased by Investigator Young and for possessing with intent to distribute the 12.72 grams of cocaine found under the truck. The government introduced expert testimony from Officer David Stroud, who testified concerning the roles and behavior of participants in drug trafficking operations. The government put to Stroud an elaborate hypothetical involving three people performing exactly the same actions as the defendants in'this case, in exactly the same location, using the same words, and even the same amounts of cocaine. Stroud testified that the scenario suggested to him a common pattern for a cocaine sale; he gave his opinion on who in the described operation was a “runner,” who was a “holder,” and who “was going to actually make the sale.”
Officer Young, who also testified about the transaction, was cross-examined concerning his ability to see Holloman at night and about his later identification of Hollo-man. In closing argument, Holloman’s counsel pressed the theory that Holloman had been misidentified at the time of the arrest. The court, however, declined to give the jury an instruction describing the difficulties often involved in identification testimony and emphasizing that the government must establish the defendants’ identification beyond a reasonable doubt.
The jury, rather puzzlingly, acquitted Marks on both counts, convicted Holloman only of distribution of the .199 grams of cocaine (he was acquitted of possession of the 12.72 grams that police found under the pickup truck), and convicted Boney of both offenses. After the verdict had been returned, but before sentencing, Holloman’s counsel received a tip that the foreman of the jury was a convicted felon. An investigation by the prosecutor confirmed that the foreman had been convicted of grand theft and taking a vehicle without consent in California and had been arrested for larceny in Arizona. Boney and Holloman claimed that the felon’s presence on the jury had violated their Sixth Amendment rights, and they moved for a new trial. The court denied their motion.
Even though Holloman had been acquitted of the possession charge, the court calculated both Boney’s and Holloman’s sentences by aggregating the weight of drugs involved in both counts (.199 grams on the distribution count and 12.72 grams on the possession count). Under the Sentencing Guidelines, that amount of drugs produces a sentencing range of 63-78 months for each defendant. The district court sentenced Boney to 78 months, but gave Holloman credit for accepting responsibility and sentenced him to 63 months.
Boney and Holloman appeal their convictions. Boney contends that Officer Stroud’s expert testimony was inadmissible because it was both unhelpful to the jury under Fed.R.Evid. 702 and unduly prejudicial under Fed.R.Evid. 403. Holloman charges that the court erred in refusing to instruct the jury on the issue of identification. Both claim that the presence of a felon on the jury violated the Sixth Amendment and requires a new trial. Finally, Holloman also argues that the district court violated the Due Process and Double Jeopardy Clauses of the Fifth Amendment by calculating his sentence based on the weight of drugs involved in a count on which he was acquitted.
II.
We turn first to Boney’s challenge to the expert testimony of Officer Stroud. According to Boney, the hypothetical presented by the prosecutor so closely mirrored the facts in this case that by assigning roles to the individuals in the hypothetical, Officer Stroud essentially gave his opinion that Boney and Holloman were playing those roles in a cocaine sale. Boney asserts that such testimony was not helpful to the jury as required by Fed.R.Evid. 702 and that it was unduly prejudicial under Fed.R.Evid. 403.
We consider appellant’s arguments under Rule 702 and Rule 403 separately because only the Rule 702 objection was preserved at trial. The district court’s admission of the expert testimony under Rule 702 is subject to reversal only for abuse of discretion. See United States v. Dunn, 846 F.2d 761, 763 (D.C.Cir.1988). Rule 702 permits expert testimony that “assist[s] the trier of fact to understand the evidence or to determine a fact in issue.” Fed.R.Evid. 702. Under that requirement that expert testimony “assist” the jury (usually referred to as the “helpfulness” requirement), testimony should ordinarily not extend to matters within the knowledge of laymen. Officer Stroud’s testimony certainly did not do so. The operations of narcotics dealers repeatedly have been found to be a suitable topic for expert testimony because they are not within the common knowledge of the average juror. See, e.g., United States v. Dunn, 846 F.2d 761, 763 (D.C.Cir.1988); United States v. Carson, 702 F.2d 351, 369 (2d Cir.), cert. denied, 462 U.S. 1108, 103 S.Ct. 2456, 2457, 77 L.Ed.2d 1335 (1983).
Nevertheless, Boney contends that, although expert testimony on the operations of drug dealers in general may be admissible, Rule 702 prohibits an expert from giving an opinion that a particular defendant played a particular role in alleged criminal activity. His position is that such testimony is barred both because the helpfulness requirement of the rule implicitly prohibits testimony on matters that jurors are expected to infer on their own, and because the testimony comes too close to a direct opinion on guilt or innocence,which would also be proscribed. See, e.g., United States v. Lockett, 919 F.2d 585, 590 (9th Cir.1990). Boney notes that the Second Circuit has expressed “discomfort” with testimony that connects particular defendants to roles in criminal conduct, see Boissoneault, 926 F.2d at 233, and has stated that “an expert should not be permitted to testify that the defendant’s actions fit a pattern of conduct which the expert had observed in prior narcotics investigations.” United States v. Cruz, 797 F.2d 90, 96 (2d Cir.1986).
Officer Stroud did express an opinion about the actions of the defendants in this case—the government’s thinly disguised hypothetical did not render his statements a mere abstract assessment of an imaginary scenario. Nonetheless, Rule 702 does not bar an expert from drawing conclusions in a specific case, including a conclusion that the defendant was involved in illegal activity or playing a specific role in illegal activity. The Rule does not confine an expert to general statements in the field of his expertise; it does not require that any inferences from the facts in the specific case be left to the jury. Although it may be well that an expert should not draw inferences a jury could make for itself, see, e.g., Boissoneault, 926 F.2d at 233, by stating that the defendants’ actions fit the pattern of a typical drug sale, Officer Stroud did not draw a conclusion so obvious that it could be thought he invaded the juror’s province. Cf. United States v. Arenal, 768 F.2d 263, 270 (8th Cir.1985) (holding that the jury would have been competent on its own to conclude that several samples of cocaine all cut with only one agent were from the same source). His testimony was similar to a statement that a defendant’s actions mirrored a common criminal modus operandi—a form of testimony generally allowed. See United States v. Espinosa, 827 F.2d 604, 612 (9th Cir.1987), cert. denied, 485 U.S. 968, 108 S.Ct. 1243, 99 L.Ed.2d 441 (1988); United States v. Stewart, 770 F.2d 825, 831 (9th Cir.1985), cert. denied, 474 U.S. 1103, 106 S.Ct. 888, 88 L.Ed.2d 922 (1986); United States v. Maher, 645 F.2d 780, 783-84 (9th Cir.1981) (per curiam).
The Second Circuit, however, has objected to such testimony on the slightly different ground that it would be “rather offensive” to allow an expert to approach the ultimate conclusion in the case by testifying that a particular defendant’s actions fit a known pattern of criminal conduct. See United States v. Brown, 776 F.2d 397, 401 (2d Cir.1985), cert. denied, 475 U.S. 1141, 106 S.Ct. 1793, 90 L.Ed.2d 339 (1986). Still, it is part of the normal role of the expert not merely to describe patterns of conduct in the abstract, but to connect actions in a specific case to those patterns— sometimes even to the point of testifying that the defendant was involved in criminal conduct. See, e.g., United States v. Carson, 702 F.2d 351 (2d Cir.), cert. denied, 462 U.S. 1108, 103 S.Ct. 2456, 2457, 77 L.Ed.2d 1335 (1983). The Second Circuit’s marked ambivalence toward such testimony perhaps reflects a concern that as experts depart from general testimony and draw conclusions about criminal conduct in the cases before them, they approach what is generally accepted to be forbidden ground because their opinions verge on conclusions concerning the defendant’s guilt.
We say generally accepted but note that that proposition is by no means obvious from examination of the Federal Rules of Evidence. At one time an expert was prohibited from testifying on any ultimate issue to be determined by the trier of fact. See, e.g., United States v. Spaulding, 293 U.S. 498, 506, 55 S.Ct. 273, 276, 79 L.Ed. 617 (1935). Rule 704(a) specifically removed that prohibition and now expressly permits expert testimony on “ultimate issue[s] to be decided by the trier of fact.” Fed.R.Evid. 704(a). On the other hand, the commentary to Rule 704 states that, despite the change, Rule 702 (and Rule 403) may still be used to exclude “opinions which would merely tell the jury what result to reach.” Fed.R.Evid. 704, Note of Advisory Committee on 1972 Proposed Rules. The Fifth Circuit has accordingly regarded the question of guilt or innocence as entailing a legal conclusion rather than an issue for the trier of fact, see United States v. Masson, 582 F.2d 961, 964 n. 5 (5th Cir.1978); see also Owen v. Kerr-McGee Corp., 698 F.2d 236, 240 (5th Cir.1983), and the Ninth Circuit has consistently held that an expert may not give a direct opinion on the defendant’s guilt or innocence, although the court has never been specific in its reasoning. United States v. Lockett, 919 F.2d 585, 590 (9th Cir.1990); United States v. Kinsey, 843 F.2d 383, 388 (9th Cir.), cert. denied, 488 U.S. 836, 109 S.Ct. 99, 102 L.Ed.2d 75 (1988); United States v. Fleishman, 684 F.2d 1329, 1335-36 (9th Cir.), cert. denied, 459 U.S. 1044, 103 S.Ct. 464, 74 L.Ed.2d 614 (1982). That position would seem supported by Rule 704(b), which bars an expert from testifying that the defendant had “the mental state or condition constituting an element of the crime charged,” Fed.R.Evid. 704(b). An opinion that the defendant is guilty necessarily incorporates a conclusion that the defendant had the requisite mental state to meet all elements of the offense. Although the overlapping nature of the provisions treating expert testimony can understandably produce some confusion regarding the precise rule to be relied on to exclude an opinion as to guilt, we agree that a direct opinion on guilt or innocence would be barred and that Rule 702 is a plausible vehicle for challenging such testimony.
Appellant’s contentions, however, would require us to go further. Appellant essentially argues that if we accept the general view — that an expert witness must not testify directly as to a defendant’s guilt or innocence — we are led inexorably to the Second Circuit’s episodic objection to testimony that is the functional equivalent of the forbidden. We disagree. We accept the Fifth and Ninth Circuits’ view that an expert may not testify on the ultimate question of guilt or innocence, but find no warrant in the Federal Rules to extend that prohibition. We think that no coherent line can be drawn beyond that restriction and that the effort to find such a boundary has caused the tension we perceive in the Second Circuit’s opinions.
Officer Stroud’s testimony, which at most matched particular defendants and their actions with paradigm roles in an illegal enterprise, does not amount to a direct opinion on the defendants’ guilt. See Fleishman, 684 F.2d at 1335-36; United States v. Masson, 582 F.2d 961, 964 & n. 5 (5th Cir.1978). Concluding that a defendant’s actions (as described by the prosecutor) suggest that the defendant played a given role in a criminal enterprise is not the same as telling the jury that the government has proved every element of its case and that the defendant is guilty as charged.
Indeed, in United States v. Dunn, 846 F.2d 761 (D.C.Cir.1988), we permitted testimony similar to Officer Stroud’s. There an expert concluded that the nature of activities in a townhouse suggested “a retail operation used for the everyday distribution, distributing of primarily crack and heroin.” Id. at 762. Officer Stroud similarly opined that the actions described in this case suggested a “runner and holder” type of drug sale and that appellants’ actions fit certain roles in the “runner and holder” operation. In Dunn, we did not read Rule 702 to bar the expert’s conclusion that the facts described an illegal drug operation. The addition in this case of somewhat more specific treatment of individual roles does not warrant a different result under the Rule, and, therefore, we reject appellant’s claim.
Nevertheless, we echo here the cautionary note we sounded in United States v. Anderson: “[TJhere is often an inherent danger with expert testimony unduly biasing the jury ‘because of its aura of special reliability and trust.’ ” 851 F.2d 384, 393 (D.C.Cir.1988) (quoting United States v. Amaral, 488 F.2d 1148, 1152 (9th Cir.1973)), cert. denied, 488 U.S. 1012, 109 S.Ct. 801, 102 L.Ed.2d 792 (1989). We note that in cases such as this, it is within the trial court’s discretion to exclude under Fed.R.Evid. 403 expert testimony that goes beyond a description of criminal modus operandi in general and assigns specific roles to individual defendants if the court deems it unfairly prejudicial.
In this case, however, Boney did not ask the trial judge to exercise discretion under Rule 403. Although Boney argues on appeal that Stroud’s testimony was inadmissible under Rule 403, his objections at trial were not specific enough to raise that issue. Our recognition of the threat expert testimony may pose for “unduly biasing the jury,” Anderson, 851 F.2d at 393, does not mean that every objection to expert testimony automatically includes an objection that the testimony is unduly prejudicial under Rule 403. Precisely because Rule 403 requires the trial court to undertake a subtle balancing to determine whether the probative value of the evidence outweighs its prejudicial effect, the trial judge must be alerted to the need to balance by a timely and specific objection.
Even though appellant did not preserve an objection under Rule 403 at trial, we still must review admission of the expert testimony for plain error, see Fed. R.Evid. 103(d), which means we cannot reverse “other than in extraordinary circumstances ‘affectpng] substantial rights and resulting] in a miscarriage of justice.’ ” United States v. Johnson, 802 F.2d 1459, 1465 (D.C.Cir.1986) (quoting United States v. Johnson, 722 F.2d 407, 409 (8th Cir.1983)). It is difficult to imagine a Rule 403 challenge that could meet this exacting standard, for Rule 403 contemplates the thoughtful consideration of the trial court and leaves the admission of evidence to the sound discretion of the trial judge. As the Third Circuit stated in United States v. Long, 574 F.2d 761, 767 (3d Cir.), cert. denied, 439 U.S. 985, 99 S.Ct. 577, 58 L.Ed.2d 657 (1978), “If judicial self-restraint is ever desirable, it is when a Rule 403 analysis of a trial court is reviewed by an appellate tribunal.” In any event, in this case we think the district judge could quite reasonably have thought the value of Stroud’s testimony connecting the defendants to identifiable roles in a drug sale outweighed its prejudicial effect. And, in hindsight it seems rather clear that whatever prejudicial impact the testimony may have carried, it did not overly influence the jurors, for despite Stroud’s suggestion that Marks had been the “runner” in this drug operation, the jury acquitted Marks on both counts.
III.
Appellant Holloman argues that the district court erred in refusing to instruct the jury on the issue of identification. He claims that when identification is a prominent issue, our decisions in Salley v. United States, 353 F.2d 897 (D.C.Cir.1965), and Macklin v. United States, 409 F.2d 174 (D.C.Cir.1969), oblige a district court to give an identification instruction when one is requested.
In Salley we held that it was reversible error for the district court to refuse the defendant’s request for an instruction on mistaken identification. See Salley, 353 F.2d at 898-99. But in Jones v. United States, 361 F.2d 537 (D.C.Cir.1966), we “emphasized the narrow limitations of our ruling in Salley,” id. at 542, and restricted the holding to fact patterns that revealed some special difficulty in the identification. Salley presented just such complications because there “an undercover narcotics agent attempted] to isolate in his recollection the identity of one participant in as many as a 100[sic] similar transactions.” Jones, 361 F.2d at 542.
Our holding in Macklin was similarly limited. Although we said that in cases in which identification is a major issue the court should instruct the jury on identification sua sponte, see Macklin, 409 F.2d at 178, our suggestion must be read as precatory. We have not subsequently reversed a district court for failing to offer such an instruction unless particular difficulties complicated the identification testimony in the case. Thus, in United States v. Telfaire, 469 F.2d 552 (D.C.Cir.1972), we analyzed the “prejudice inherent in the failure of the trial court to offer” an identification instruction, id. at 555-56, but declined to reverse because the “case exhibited] none of the special difficulties often presented by identification testimony that would require additional information be given to the jury in order for us to repose confidence in their ability to evaluate the reliability of the identification,” id. at 556. The Fourth Circuit thus summarized our cases accurately when it stated that the instruction is “compelled” only when there are “special difficulties,” United States v. Brooks, 928 F.2d 1403, 1406 (4th Cir.), cert. denied, — U.S. -, 112 S.Ct. 140, 116 L.Ed.2d 106 (1991) — in the absence of such circumstances the failure to instruct is not error.
Officer Young’s identification of Holloman in this case presented no special difficulties. Young executed a single transaction face to face with Holloman in an area lit by streetlights. Within minutes he radioed a description of Holloman to his team, and shortly thereafter he identified Holloman at the scene of the arrest.
IV.
Boney and Holloman also argue that the district court erred in refusing to grant their motion for a new trial in light of the discovery, after conviction but before sentencing, that one of the jurors in their trial was a felon. The appellants contend that in this situation the Sixth Amendment guarantee of an impartial jury requires a new trial. They urge us to interpret the Sixth Amendment in light of 28 U.S.C. §§ 1865-1867 which govern the jury selection process.
The appellants eschew direct reli-anee on 28 U.S.C. §§ 1865-1867 because the statutory remedy would appear time-barred. We think the statute is inapplicable to the appellants, but not just because their objection to a juror who concealed his felon status was untimely. Rather, 28 U.S.C. §§ 1865-1867 do not help appellants because those provisions address a different problem — the procedures by which the district court should administer the jury selection process. Section 1865 requires a district court official to exclude certain groups of jurors, including both convicted felons and individuals accused of a felony, pursuant to status-based disqualifications. 28 U.S.C. § 1865(b)(5). But § 1867 establishes strict procedural limitations on the ability of parties to raise objections to the jury selection process. Subsection 1867(a) allows the defendant to object “before the voir dire examination begins, or within seven days after the defendant discovered or could have discovered, by the exercise of diligence, the grounds therefor, whichever is earlier.” 28 U.S.C. § 1867(a). And subsection 1867(e) emphasizes that the § 1867 procedures constitute the “exclusive means” by which parties can challenge the jury for improper selection. 28 U.S.C. § 1867(e). These provisions do not apply directly to our case, however, because when a juror fails to disclose his felon status on the jury qualification form, no defect in the court’s jury selection process occurs.
Insofar as 28 U.S.C. §§ 1865-1867 are relevant to our analysis, moreover, they counsel against any rule that would lead to automatic reversal. The statutory scheme permits a conviction to stand in the face of an untimely allegation that the district court allowed a felon juror to serve in violation of the proper jury selection, process. For example, if a juror acknowledged his felon status on the jury qualification form but was permitted to serve in violation of § 1865, § 1867 would bar an untimely challenge to his service. See, e.g., United States v. Uribe, 890 F.2d 554, 561 (1st Cir.1989) (“Like so many statutory rights, the right to exclude felons must be affirmatively invoked.”). To be sure, § 1865 evinces a congressional purpose to restrict the service of felons on juries. The strict procedural limitations of § 1867, however, make abundantly clear that other values, such as judicial efficiency and finality, tempered Congress’ desire to bar felon-jurors and led Congress to reject a rule of per se reversal.
The Sixth Amendment right to an impartial jury similarly does not require an absolute bar on felon-jurors. The Supreme Court has stressed repeatedly that the touchstone of the guarantee of an impartial jury is a protection against juror bias. See, e.g., McDonough Power, Equipment, Inc. v. Greenwood, 464 U.S. 548, 554, 104 S.Ct. 845, 849, 78 L.Ed.2d 663 (1984). Á per se rule would be appropriate, therefore, only if one could reasonably conclude that felons are always biased against one party or another. But felon status, alone, does not necessarily imply bias. In fact, as the dissent suggests, Congress’ purpose in restricting felons’ jury service may stem from considerations other than a concern for biased jurors. Dissent at 637-38. More important, a per se rule requiring a new trial whenever it turns out that a felon served on a jury seems inconsistent with McDonough’s hostility to unnecessary new trials, id. at 553-54, 104 S.Ct. at 848-49, and the oft-repeated axiom that “[a defendant] is entitled to a fair trial but not a perfect one.” Lutwak v. United States, 344 U.S. 604, 619, 73 S.Ct. 481, 490, 97 L.Ed. 593 (1953). We think, therefore, that the Sixth Amendment guarantee of an impartial trial does not mandate a per se invalidation of every conviction reached by a jury that included a felon. Accord United States v. Uribe, 890 F.2d 554, 562 (1st Cir.1989); United States v. Currie, 609 F.2d 1193, 1194 (6th Cir.1979) (per curiam), cert. denied, 445 U.S. 928, 100 S.Ct. 1314, 63 L.Ed.2d 760 (1980); Ford v. United States, 201 F.2d 300, 301 (5th Cir.1953); cf. Raub v. Carpenter, 187 U.S. 159, 163, 23 S.Ct. 72, 73, 47 L.Ed. 119 (1902) (denying a motion for a new trial in a civil case).
Even though the Sixth Amendment does not require automatic reversal, there is still the question whether appellants were entitled to a hearing to determine whether the juror was in fact biased. Although the discovery of the juror’s felon status does not by itself require a new trial, we think the juror’s failure to disclose his status in response to the voir dire examination presents serious added concerns. After all, lying or failing to disclose relevant information during voir dire itself raises substantial questions about the juror’s possible bias. While refusing to adopt a per se rule requiring a new trial in United States v. North, 910 F.2d 843 (D.C.Cir.1990), cert. denied, — U.S.-, 111 S.Ct. 2235, 114 L.Ed.2d 477 (1991), we recognized the seriousness of a juror’s deliberate concealment of relevant information during voir dire. We assumed that a district court should grant a new trial upon a showing of actual bias and affirmed the district court’s denial of a motion for a new trial because it had held an evidentiary hearing and found no bias. Id. at 904-05; see also United States v. Currie, 609 F.2d 1193, 1194 (6th Cir.1979) (per curiam) (affirming the district court’s denial of a motion for a new trial after an evidentiary hearing determined that those jurors who had lied about their felon status were not biased against the defendant), cert. denied, 445 U.S. 928, 100 S.Ct. 1314, 63 L.Ed.2d 760 (1980).
In this case, however, the district court judge denied the defendant’s motion for an evidentiary hearing. To be sure, our reliance in North on the district judge’s evidentiary hearing did not settle the question whether a hearing is required when it is revealed after trial that a juror had concealed relevant information. The Supreme Court, likewise, has not directly faced this issue, but it has noted the general principle “that the remedy for allegations of juror partiality is a hearing in which the defendant has the opportunity to prove actual bias.” Smith v. Phillips, 455 U.S. 209, 215, 102 S.Ct. 940, 945, 71 L.Ed.2d 78 (1982). We think the district judge was obliged to conduct such a hearing here. Cf. Hard v. Burlington N.R.R., 812 F.2d 482, 484 (9th Cir.1987) (ruling that, under the facts of that case, the district court’s failure to grant an evidentiary hearing about juror dishonesty was an abuse of discretion). We do not now hold that any false statement or deliberate concealment by a juror necessitates an evidentiary hearing. But we believe that a juror’s refusal to admit his felony status is particularly troublesome. Unlike some information sought in voir dire, a question about felon status would strike the average juror as extremely serious and sensitive. Lying about a factor as important (and as easy to verify through public records) as felon status raises at least the inference that the juror had an undue desire to participate in a specific case, perhaps because of partiality. Because the record provides no evidence that the motivation for the lie was unrelated to bias in this case, it was an abuse of discretion under these facts for the trial judge not to have held an eviden-tiary hearing.
We therefore remand this case for the district court to hold an evidentiary hearing to determine whether the juror’s failure to disclose his felon status resulted in actual bias to the appellants.
V.
Appellant Holloman also claims that his sentence was improper. Although Hollo-man was convicted only of distribution of .199 grams of cocaine and acquitted of possession with intent to distribute the 12.72 grams that Boney had under the pickup truck, the presentence report aggregated the two amounts of cocaine and calculated an offense level based on the combined weight of 12.919 grams. The offense level determined a sentencing range of 63 to 78 months, well within the statutory maximum of 20 years set by 21 U.S.C. § 841(b)(1)(C), but far above the range of 10 to 16 months that would have applied had only the .199 grams been used to calculate the offense level.
The district court, finding by at least a preponderance of the evidence that Hollo-man also possessed the 12.72 grams of cocaine discovered under the pickup truck, considered that “relevant conduct” under § lB1.3(a) of the Guidelines and sentenced Holloman to 63 months. Had Hollo-man been convicted on the possession with intent to distribute count, the same sentencing range of 63 to 78 months would have applied. Holloman argues that the Sentencing Guidelines do not permit consideration of the drugs involved in the count on which he was acquitted. And he contends that by considering those drugs in sentencing and by giving him the same sentence that he could have received had he been convicted on both counts, the district court violated the Double Jeopardy and Due Process Clauses of the Fifth Amendment.
The appellants’ argument is offered in the face of overwhelming prior judicial rejection; a full ten circuits have authorized the use of acquitted conduct in sentencing under the Sentencing Guidelines. See United States v. Coleman, 947 F.2d 1424, 1428-29 (10th Cir.1991); United States v. Rivera-Lopez, 928 F.2d 372, 372-73 (11th Cir.1991) (per curiam); United States v. Fonner, 920 F.2d 1330, 1332-33 (7th Cir.1990); United States v. Duncan, 918 F.2d 647, 652 (6th Cir.1990), cert. denied, — U.S.-, 111 S.Ct. 2055, 114 L.Ed.2d 461 (1991); United States v. Rodriguez-Gonzalez, 899 F.2d 177, 180-81 (2d Cir.), cert. denied, — U.S. -, 111 S.Ct. 127, 112 L.Ed.2d 95 (1990); United States v. Dawn, 897 F.2d 1444, 1449-50 (8th Cir.), cert. denied, — U.S. -, 111 S.Ct. 389, 112 L.Ed.2d 400 (1990); United States v. Mocciola, 891 F.2d 13, 16-17 (1st Cir.1989); United States v. Isom, 886 F.2d 736, 738-39 (4th Cir.1989); United States v. Juarez-Ortega, 866 F.2d 747, 748-49 (5th Cir.1989); United States v. Ryan, 866 F.2d 604, 608-09 (3d Cir.1989). Only the Ninth Circuit, over a strong dissent by Chief Judge Wallace, has rejected the use of acquitted conduct in sentencing, and it did not rest its decision on constitutional grounds. See United States v. Brady, 928 F.2d 844, 851-52 & n. 14 (9th Cir.1991).
The “relevant conduct” upon which the Guidelines require that an offense level be based is, for drug related offenses, sweepingly defined to include “all such acts and omissions that were part of the same course of conduct or common scheme or plan as the offense of conviction.” U.S.S.G. § lB1.3(a)(2). That language is certainly broad enough to include acts underlying offenses of which the defendant has been acquitted. Indeed, the application notes make clear that conduct may be relevant for sentencing even if the defendant was not convicted on any count involving that conduct. See id. § 1B1.3, Commentary Application Note 2. Section 6A1.3(a) of the Guidelines allows a broad range of information to be used in sentencing and requires simply that the information have “sufficient indicia of reliability to support its probable accuracy.” U.S.S.G. § 6A1.3(a). Congress also has endorsed an expansive view of the information that may be used in sentencing: “No limitation shall be placed on the information concerning the background, character, and conduct of a person convicted of an offense which a court ... may receive and consider for the purpose of imposing an appropriate sentence.” 18 U.S.C. § 3661. We will, therefore, leave the Ninth Circuit in isolation on this issue and join, instead, the other ten circuits in holding that Sentencing Guidelines allow the use in sentencing of conduct underlying acquitted counts.
Holloman’s constitutional challenges are not significant. Holloman argues that use of the acquitted conduct to enhance his sentence violated the Double Jeopardy Clause by punishing him for an offense of which he was acquitted. Even assuming that the Double Jeopardy Clause, rather than the Due Process Clause, would protect a defendant from being sentenced for a charge of which he was acquitted, Holloman's argument “misperceives the distinction between a sentence and a sentence enhancement.” Mocciola, 891 F.2d at 17. The district court did not impose a separate sentence on Holloman for the possession count. Rather, it considered the drugs involved in that count to enhance his sentence within the statutory range for the distribution offense of which he was convicted: “the acquitted conduct merely affected the point within the statutory range at which his sentence was imposed.” Rodriguez-Gonzalez, 899 F.2d at 181. In the absence of a separate punishment for the acquitted conduct, Holloman does not have an arguable claim based on the Double Jeopardy Clause.
Holloman’s due process argument is based on the false assumption that his acquittal is equivalent to a finding of complete innocence. But a not guilty ver-diet simply indicates that guilt was not proved beyond a reasonable doubt; it does not establish that the defendant played no part in the charged conduct. See, e.g., Fonner, 920 F.2d at 1332; Isom, 886 F.2d at 738; cf United States v. One Assortment of 89 Firearms, 465 U.S. 354, 361-62, 104 S.Ct. 1099, 1104, 79 L.Ed.2d 361 (1984). Conduct underlying the acquittal may be used in sentencing as long as it is proved by a standard that satisfies due process. Although Holloman’s assertions imply that the Constitution requires proof beyond a reasonable doubt in sentencing, it is well established that “due process is satisfied so long as facts necessary for sentencing are proved by a preponderance of the evidence.” United States v. Burke, 888 F.2d 862, 869 (D.C.Cir.1989); see also McMillan v. Pennsylvania, 477 U.S. 79, 91-92, 106 S.Ct. 2411, 2418-19, 91 L.Ed.2d 67 (1986) (approving the same standard in the context of state sentencing). Because the sentencing court found by at least a preponderance of the evidence that Holloman possessed the 12.72 grams of cocaine, it committed no constitutional error in considering that cocaine to enhance his sentence.
Admittedly, Holloman received the same sentence he would have had if he had been convicted on the possession count. That result is rather anomalous and is certainly unlucky from Holloman’s perspective, but it is not unconstitutional. Neither due process nor the Double Jeopardy Clause requires that a defendant convicted on multiple counts under the same statute receive a different sentence from a defendant convicted on only one count. The result in Holloman’s case is merely a consequence of Congress’ decision to make both distribution and possession with intent to distribute the same substantive offense under 21 U.S.C. § 841(a) and to base sentencing on the weight of drugs involved.
* * * * * *
Accordingly, we reject all of the challenges the appellants raise against their convictions except their argument that the Sixth Amendment requires an evidentiary hearing to determine whether a juror’s failure to disclose his felon status resulted in actual bias against the appellants. We remand to the district court to hold such a hearing.
It is so ordered.
. Contrary to the government's assertion, Boney’s counsel did raise an objection under Rule 702 at trial. Before Officer Stroud began to testify, Boney’s counsel protested that "you really don’t need an expert. There is nothing complicated in this case.... ” He also objected to testimony concerning the defendants' "roles and so forth." Finally, he objected to the government’s detailed hypothetical after the prosecutor had described it but before Officer Stroud had answered. These objections were sufficiently specific, see Fed.R.Evid. 103, to alert the district court and opposing counsel that appellant's counsel considered expert testimony unhelpful to the jury and thus barred by Rule 702.
. Other circuits have stated that a district court's admission of expert testimony will be overturned only if manifestly erroneous. See, e.g., United States v. Boissoneault, 926 F.2d 230, 232 (2d Cir. 1991); United States v. Espinosa, 827 F.2d 604, 611 (9th Cir.1987), cert. denied, 485 U.S. 968, 108 S.Ct. 1243, 99 L.Ed.2d 441 (1988). We understand these circuits to be applying the same test that we apply here.
. The Brown court nevertheless held that expert testimony concluding that the defendant had played the role of a "steerer" in a narcotics operation was admissible. See Brown, 776 F.2d at 401-02.
. Although Boney claims that in Cruz the Second Circuit barred testimony connecting a specific defendant to a common criminal modus operandi, the law in that circuit is not as clear as he suggests. The Second Circuit has stated recently that an "expert may generally suggest inferences that should be drawn from the facts, including inferences embracing the ultimate issue in the case," Boissoneau.lt, 926 F.2d at 232 (citation omitted), and has noted that it has "permitted experts to make conclusory statements, based on their experience, that the defendant was involved in illegal drug-related activity.” Id. at 233 (citing United States v. Brown, 776 F.2d 397 (2d Cir.1985), cert. denied, 475 U.S. 1141, 106 S.Ct. 1793, 90 L.Ed.2d 339 (1986); United States v. Young, 745 F.2d 733 (2d Cir. 1984), cert. denied, 470 U.S. 1084, 105 S.Ct. 1842, 85 L.Ed.2d 142 (1985); and United States v. Carson, 702 F.2d 351 (2d Cir.), cert. denied, 462 U.S. 1108, 103 S.Ct. 2456, 2457, 77 L.Ed.2d 1335 (1983)). In fact, the language appellant cites from Cruz mischaracterizes the holding in Brown, a case in which the Second Circuit refused to find error in the admission of an expert’s opinion that a defendant had been playing the role of a "steerer” in a narcotics sale. See Brown, 776 F.2d at 401-02.
. That confusion was apparent in this case, for while appellant relied solely on Rules 702 and 403 in pressing his appeal, the government responded as if appellant's argument had been based on Rule 704(b).
. The government argues that appellant Hollo-man did not properly object to the jury instruction at trial. In fact, Holloman’s counsel effectively objected to the instruction twice. Before the charge was given, Holloman's counsel stated that she would make objections on behalf of all three defendants and that counsel for Marks and Boney would "chime in.” Counsel for Boney then objected to the decision not to give an identification instruction. The earlier statement by Holloman’s counsel was sufficient, however, to alert the court that all three defendants were joining each other’s objections. Furthermore, after the charge had been given, but before the jury retired, the trial court allowed another opportunity for objections. Counsel for Holloman then clearly objected to the lack of an identification instruction. Because Fed. R.Crim.P. 30 requires only that an objection to the charge be raised before the jury retires to consider its verdict, Holloman’s objection was sufficient.
. Although McDonough involved a juror’s failure to disclose information during the voir dire examination in a civil case, we have applied McDonough to criminal trials. See United States v. North, 910 F.2d 843, 904 (D.C.Cir. 1990), cert. denied, -U.S. -, 111 S.Ct. 2235, 114 L.Ed.2d 477 (1991).
. The dissent finds support for a per se rule in the power of a trial judge to strike jurors for cause and grant a new trial in the interests of justice. Dissent at 639; 643. That the trial judge possesses this power does not suggest that it was error for him to decline to exercise it. Our review of that decision is governed by the abuse of discretion standard. The dissent, however, would use the existence of the trial judge’s discretion to fashion a rule promulgated by the court of appeals — a rule which permits a defendant to challenge his conviction, because a felon sat on his jury, at least at any time before judgment is entered and presumably later through a post-judgment motion for a new trial or on direct appeal and perhaps years later under § 2255. See 28 U.S.C. § 2255. That appears to be straightforward federal policymak-ing, which we think is reserved to Congress.
. All other things equal, the likelihood that a juror who conceals information is biased increases with the likelihood that disclosure of the information will lead to his disqualification. Because the disclosure of a felon status during trial leads to almost certain disqualification, concern about concealing that status is particularly appropriate.
. In fact, the sentencing court suggested that Holloman’s possession of the 12.72 grams of cocaine had been shown beyond a reasonable doubt.
. Relying on the above provisions we have already approved the use in sentencing of the weight of drugs involved in uncharged criminal conduct and dismissed counts. See United States v. Chaikin, 960 F.2d 171, 174 (D.C.Cir.1992); United States v. Salmon, 948 F.2d 776, 778 (D.C.Cir.1991). Similarly, we have allowed the use in sentencing of evidence seized in violation of the Fourth Amendment. See United States v. McCrory, 930 F.2d 63, 67-69 (D.C.Cir.1991), cert. denied, — U.S.-, 112 S.Ct. 885, 116 L.Ed.2d 788 (1992). Conduct underlying an acquittal does not require different treatment under the Guidelines.