2001 Decisions

Opinions of the United

States Court of Appeals

for the Third Circuit

8-30-2001

United States v. Mathis

Precedential or Non-Precedential:

Docket 99-5940

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Recommended Citation

"United States v. Mathis" (2001). 2001 Decisions. Paper 200.

http://digitalcommons.law.villanova.edu/thirdcircuit_2001/200
Filed August 30, 2001 

UNITED STATES COURT OF APPEALS 

FOR THE THIRD CIRCUIT 

No. 99-5940 

UNITED STATES OF AMERICA 

Appellee 

v. 

KEITH MATHIS 

Appellant 

On Appeal from the United States District Court 

for the District of New Jersey 

NO. 98-cr-656-2 

District Judge: Honorable Alfred J. Lechner, Jr. 

Argued June 1, 2000 

Before: SCIRICA and NYGAARD, Circuit Judges and 

POLLAK,* District Judge 

(Filed: August 30, 2001) 

_________________________________________________________________ 

* Honorable Louis H. Pollak, United States District Judge for the 

Eastern District of Pennsylvania, sitting by designation. 
 Robert J. Cleary, Esq. 

 George S. Leone, Esq. 

 Phillip H. Kwon, Esq. (argued) 

 United States Attorney 

 Assistant United States Attorney 

 970 Broad Street 

 Room 700 

 Newark, NJ 07102 

 Counsel for Appellee United States 

 of America 

 Mark A. Berman, Esq. (argued) 

 Peter J. Torcicollo, Esq. 

 Gibbons, Del Deo, Dolan, 

 Griffinger & Vecchione 

 One Riverfront Plaza 

 Newark, NJ 07102 

 Counsel for Appellant 

OPINION OF THE COURT 

POLLAK, District Judge: 

This appeal concerns three challenges to Keith Mathis's 

conviction for bank robbery and conspiracy to commit bank 

robbery. First, Mr. Mathis claims that the District Court 

wrongly admitted into evidence testimony describing his 

involvement in previous, uncharged bank robberies. 

Second, Mr. Mathis asserts that the District Court erred in 

admitting evidence that his picture was selected from a 

photographic array, because the array was 

unconstitutionally suggestive. Third, Mr. Mathis argues 

that the District Court wrongly excluded expert testimony 

that called into question eyewitness testimony identifying 

Mr. Mathis as he fled from the robbery. As described 

herein, we disagree with Mr. Mathis's first and second 

arguments on their merits; with respect to the third, we 

hold that the District Court erred in part, but we find it 

highly improbable that such error affected the jury's 

decision. Thus, we affirm Mr. Mathis's conviction. 

 2 
I. Background 

On October 20, 1998, a grand jury indicted Mr. Mathis, 

Steven Gantt, and Jeffrey Seaberry on one count of bank 

robbery, in violation of 18 U.S.C. SS 2113(a) and 2, and one 

count of conspiracy to commit bank robbery, in violation of 

18 U.S.C. S 371. The indictment charged the three men 

with conspiring, from October 11 to October 14, 1998, to 

rob the Sun National Bank in Maple Shade, New Jersey, 

and with successfully robbing that bank on October 14, 

1998. Mr. Mathis pled not guilty to both counts, and his 

trial commenced on January 19, 1999. 

At Mr. Mathis's trial, two witnesses testified that they 

saw, from an adjoining office building, three masked men 

with guns run into, and then out of, Sun National Bank. 

These witnesses testified that the three masked men drove 

away in a dark-colored Jeep. Also, several Sun National 

Bank employees testified that, when the three were inside 

the bank, one stood near the door holding two guns, while 

the other two jumped over the bank counter and took

money from tellers' drawers. Video footage taken by the 

bank's security cameras confirmed the basic details of 

these accounts. 

The prosecution's primary witnesses were Sergeant Gary 

Gubbei and one of Mr. Mathis's alleged co-conspirators, Mr. 

Gantt. Sergeant Gubbei testified that, on the morning of 

October 14, he responded to a radio dispatch describing the 

robbery and the getaway vehicle. Soon thereafter, Sergeant 

Gubbei spotted a black Jeep Cherokee with an AfricanAmerican driver in the opposing lane of traffic; Sergeant 

Gubbei turned and gave chase. After a period of pursuit, 

the Jeep left the highway and drove onto a grass median, 

where the vehicle apparently stalled and coasted to a halt. 

Three men exited the Jeep while it was still moving--the 

driver first, then a forward passenger, then a rear

passenger--and escaped over a guardrail on the highway's 

far side. The forward passenger, while stumbling over the 

guardrail, dropped a black bag containing money. The rear 

passenger carried a gun in his right hand as he exited the 

Jeep and held the weapon near his head, pointing toward 

the sky. The rear passenger momentarily looked back at 

Sergeant Gubbei before running away, and Sergeant 

 3 
Gubbei testified at trial that he was able, based on that 

brief view, to identify the fleeing man as Mr. Mathis. 

Sergeant Gubbei also testified that, at 1:00 p.m. on October 

15, he selected Mr. Mathis's picture from an eight-picture 

photographic array as depicting one of the Jeep's 

occupants. 

Mr. Gantt, who pled guilty in this case, testified that he 

and Mr. Mathis jointly robbed a total of twelve banks, 

including the Sun National Bank, and that seven of these 

robberies, including that of the Sun National Bank, also 

involved Mr. Seaberry. Mr. Gantt further testified that these 

seven robberies shared other characteristics: The robbers 

covered their faces with masks; the robbed banks were 

located near Camden, New Jersey; and Mr. Mathis often 

stood as an armed guard, while Mr. Gantt and Mr. Seaberry 

vaulted the counters and stole cash from the drawers. 

In describing the Sun National Bank robbery, Mr. Gantt 

testified that Mr. Mathis, Mr. Seaberry, and he parked a 

Jeep at the rear of the bank's parking lot, donned face 

masks, ran alongside the bank, and entered through the 

front of the building. Mr. Gantt stated that he and Mr. 

Seaberry jumped over the tellers' counters and placed 

money from the drawers in a bag they were carrying, while 

Mr. Mathis stood guard with two pistols. The three then 

returned to the Jeep. Mr. Seaberry drove, Mr. Gantt rode in 

the forward passenger's seat, and Mr. Mathis rode in the 

rear passenger's seat. Mr. Gantt testified that, as the Jeep 

tried to evade a pursuing police cruiser (apparently driven 

by Sergeant Gubbei), Mr. Seaberry tried to drive over the 

highway's grass divider, causing the Jeep's engine to stall, 

and the three men exited while the vehicle was still rolling 

forward. Mr. Gantt stated that he and Mr. Mathis jumped 

over the highway guardrail and, without Mr. Seaberry, 

escaped after stealing a nearby delivery truck. At trial, 

Detective Jeff Hoch testified that he arrested Mr. Seaberry 

near an apartment complex beside the highway. 

II. Grounds for Appeal 

A. Evidence of Uncharged Robberies 

At trial, the government moved in limine to admit into 

evidence testimony from Mr. Gantt concerning eleven

 4 
robberies that he and Mr. Mathis had jointly undertaken 

prior to the Sun National Bank robbery. The government 

first addressed the testimony's admissibility under Federal 

Rule of Evidence 404(b), which states: 

 Evidence of other crimes, wrongs, or acts is not 

 admissible to prove the character of a person in order 

 to show action in conformity therewith. It may, 

 however, be admissible for other purposes, such as 

 proof of motive, opportunity, intent, preparation, plan, 

 knowledge, identity, or absence of mistake or accident 

 . . . . 

Fed. R. Evid. 404(b). According to the government, the 

disputed evidence was admissible, inter alia, to show Mr. 

Mathis's familiarity with Mr. Gantt and Mr. Seaberry prior 

to the charged offense and to show the group's modus 

operandi for robbing banks. In response, Mr. Mathis

conceded that Rule 404(b) was satisfied, but he claimed 

that Mr. Gantt's testimony presented a risk of unfair 

prejudice that substantially outweighed its probative value 

and was therefore barred by Rule 403, which provides: 

 Although relevant, evidence may be excluded if its 

 probative value is substantially outweighed by the 

 danger of unfair prejudice, confusion of the issues, or 

 misleading the jury, or by considerations of undue 

 delay, waste of time, or needless presentation of 

 cumulative evidence. 

Fed. R. Evid. 403. 

The District Court admitted Mr. Gantt's testimony into 

evidence, holding, as a preliminary matter, that Rule 404(b) 

was satisfied because the testimony's description of 

uncharged acts was linked to charged conduct by"[t]he 

same general area, the same general time period, the intent 

entering into the conspiracy, the background of this, the 

familiarity [of] one with the other, the agreement among 

everyone and the knowledge with regard to how to carry out 

bank robberies." With respect to Rule 403, the District 

Court acknowledged that there was "prejudice in this 

evidence," but it also found that the evidence"possess[ed] 

great probative value." Mr. Mathis's defense was one of 

mistaken identity, and the District Court found that"[t]his 

 5 
evidence from a co-defendant links him directly to the 

crime, directly with the evidence of the police officer who 

will testify. . . . I find it is not unfairly prejudicial looking at 

what the Government must prove, what is available to the 

Government and who is going to be offering the testimony." 

When Mr. Gantt completed his testimony regarding the 

uncharged robberies, the District Court read a jury

instruction (whose substance is not challenged) limiting use 

of the testimony to showing "defendant's knowledge of the 

crime of bank robbery and . . . his familiarity with the other 

alleged co-conspirators" and to showing "that the robbery of 

Sun National Bank was part of a scheme or plan in which 

the defendant participated." The District Court stressed 

that the jury could consider such evidence "only for [those] 

limited purposes . . . [and] to use the evidence for any other 

purpose would be improper and violative of your oath." 

We review a district court's decision to admit or exclude 

evidence for abuse of discretion, and such discretion is 

construed especially broadly in the context of Rule 403. 

E.g., Hurley v. Atl. Police Dep't, 174 F.3d 95, 110 (3d Cir. 

1999). On appeal, Mr. Mathis claims that Rule 403 should 

have barred the contested portion of Mr. Gantt's testimony 

because "evidence relating to so many other uncharged 

bank robberies" inevitably prejudiced the jury"by 

demonstrating that Mathis had a propensity to rob banks." 

Appellant's Br. at 28. He also claims that such testimony 

was not significantly probative because the government 

"could establish Mathis' identity, or his association to Gantt 

. . . by Sergeant Gubbei's eyewitness identification. . . and 

[by] Steven Gantt's testimony that he was acquainted with 

Mathis and that he . . . robbed the Sun National Bank with 

the defendant." Id. at 30. 

With respect to the testimony's risk of prejudice, we agree 

with the District Court that the disputed testimony's 

description of eleven uncharged robberies, in a case seeking 

conviction on only one, entailed some risk of unfair 

prejudice. That is, the jury could well have interpreted Mr. 

Gantt's testimony as proving that Mr. Mathis was a person 

of bad character who deserved punishment independent of 

the government's particular proof regarding the Sun

National Bank robbery. But in United States v. O'Leary, 739 

 6 
F.2d 135 (3d Cir. 1984), this court held that the number of 

uncharged acts alleged, even if disproportionate to the 

number of charged acts, does not alone render admission of 

such evidence an abuse of discretion. The defendant in 

O'Leary was charged with one count of conspiracy to

distribute cocaine and five counts of possession with intent 

to distribute cocaine. Mr. O'Leary claimed that the district 

court erroneously admitted testimony stating that he had 

sold drugs on "[a]bout 20" occasions during the course of 

"[a]bout a year." Id. at 136. We affirmed the conviction, 

finding that the district court had expressly analyzed the 

defendant's Rule 403 challenge and had issued an 

instruction "clearly explaining to the jury the narrow way in 

which to use the evidence," thereby "lessen[ing] any 

possibility of prejudice." Id. Similarly, in the case at bar, the 

District Court explicitly balanced the testimony's probative 

value against its danger of unfair prejudice, and it 

instructed the jury on the permissible uses of Mr. Gantt's 

testimony.1 

The chief authority on which Mr. Mathis relies is United 

States v. Hans, 738 F.2d 88 (3d Cir. 1984), where we 

reversed a defendant's conviction for bank robbery and 

assault during the commission of a bank robbery. The 

testimony in Hans was from an FBI agent, and it described 

the surprising speed with which the defendant became a 

suspect in the case. Such testimony was deemed extremely 

prejudicial because, in context, "the only reasonable 

inference that a reasonable juror could draw from the 

testimony was that Hans was well-known as a bank robber 

_________________________________________________________________ 

1. Mr. Mathis seeks to distinguish O'Leary because the witness in that 

case answered relatively few, relatively cursory questions about the 

defendant's previous misconduct, while "the government's examination of 

Gantt regarding the details of the eleven uncharged bank robberies went 

on for 34 pages, and dominated Gantt's trial testimony." Reply Br. at 26. 

We cannot agree that the government's efficiency, or lack thereof, in 

conducting Mr. Gantt's examination significantly determines the 

resultant testimony's prejudicial effect. Here, as in O'Leary, the 

government's questions were sufficient in duration and substance to 

raise the defendant's prior misconduct as an issue, and this fact 

alone--not any claim of "undue delay, waste of time, or needless 

presentation of cumulative evidence"--is the defendant's asserted basis 

for prejudice. 

 7 
to the Detroit F.B.I." Id. at 94; id. ("[I]t is difficult to imagine 

testimony more prejudicial than [the] implication that Hans 

was known to the Detroit police as a professional bank 

robber . . . ."). Mr. Mathis has presented no argument that 

Mr. Gantt's testimony implicated the unusual risk of 

prejudice discussed in Hans, and we see no reason to 

believe it did so. Whereas the testimony in Hans generated 

untestable inferences about what was "well-known" by the 

"Detroit F.B.I.," Mr. Gantt testified directly regarding his 

own experience. Thus, Mr. Gantt's testimony was properly 

challengeable, and was in fact challenged, by vigorous 

cross-examination, which significantly mitigated its risk of 

unfair prejudice. Cf. United States v. Gonzalez-Lira, 936 

F.2d 184, 191 (5th Cir. 1991) (finding the prejudicial effect 

caused by evidence of past acts mitigated by the 

opportunity to cross-examine and by a proper limiting 

instruction); United States v. Lynn, 856 F.2d 430, 437 (1st 

Cir. 1988) (finding the risk of prejudice "especially 

distressing" where the defendant "could not . . . crossexamine the agent on the reliability of the information"). 

With respect to the other part of Rule 403's analysis, the 

District Court found that Mr. Gantt's testimony possessed 

"great probative value." On appeal, the government argues 

that the disputed testimony "was admissible to show the 

familiarity and interrelationship of Mathis, Gantt, and 

Seaberry," thereby tending to prove Mr. Mathis's conspiracy 

count. Appellee's Br. at 53-55. In evaluating this position, 

we take guidance from this court's holding in United States 

v. Scarfo, 850 F.2d 1015 (3d Cir. 1988). The defendant in 

Scarfo was convicted of conspiring to extort, and of 

extorting, money from a real estate developer. The district 

court admitted testimony from two of the defendant's coconspirators stating that, prior to the charged extortion, 

they had committed two murders pursuant to the 

defendant's orders. These co-conspirators also testified 

about numerous details of the defendant's "crime family," 

including uncharged murders, briberies, and extortions. On 

appeal, we affirmed the defendant's conviction, holding that 

"[b]ecause the government's case against the defendants 

rested on the testimony of unindicted co-conspirators, 

evidence describing their relationship to the defendants and 

providing background information to illustrate the 

 8 
witnesses' roles in the scheme was properly admitted." Id. 

at 1020. Also, in order for the jury "to realize that [the coconspirators] had been granted immunity for the very 

murders that they asserted Scarfo had ordered" and 

thereby to assess the witnesses' motive for testifying, we 

concluded that such evidence was "essential in the 

government's effort to establish the credibility of its 

disreputable, yet indispensable witness." Id. 

The charged conduct here, of course, lacks much of the 

gravity and extensiveness associated with the activities 

described in Scarfo, but the applicable legal principles are 

not so dissimilar. Mr. Mathis was indicted for a conspiracy, 

whose details the government was required to prove, and 

Mr. Gantt was the government's only witness who could 

describe the conspiracy directly. Mr. Gantt's testimony 

regarding the eleven uncharged robberies, if believed by the 

jury, explained both Mr. Gantt's role in the conspiracy and 

his motive for testifying, i.e., to fulfill his plea agreement 

and reduce his sentence. This testimony also tended to 

show that, in addition to their previous associations, Mr. 

Gantt and Mr. Mathis conspired in robbing Sun National 

Bank, on the theory that co-conspirators more often trust 

those with whom they are already intimate. Contrary to Mr. 

Mathis's argument that the disputed testimony was 

unnecessary given other evidence in the case, Mr. Gantt's 

testimony was the only direct evidence offered for the 

purposes listed above. Accordingly, for reasons parallel to 

those in Scarfo, we deem Mr. Gantt's testimony significantly 

probative of Mr. Mathis's involvement in the charged 

conspiracy.2 

_________________________________________________________________ 

2. The government also argues that Mr. Gantt's testimony demonstrates 

a common modus operandi. The government's position begins with the 

solid premise that "[a] jury can rationally infer from evidence that the 

defendant committed a prior crime in an unusual and distinctive manner 

and evidence that a second similar crime was committed in the same 

unusual and distinctive manner that the defendant committed the 

second crime." Gov't of Virgin Islands v. Pinney, 967 F.2d 912, 916 (3d 

Cir. 1992). In order to distinguish this type of inference from 

impermissible conclusions based on propensity or bad character, 

however, the admissibility of such evidence critically depends on the 

degree to which the "manner" employed is "unusual and distinctive." 1 

 9 
After reviewing the District Court's explanation for its 

ruling, we find no abuse of discretion in the District Court's 

conclusion that the disputed testimony's danger of unfair 

prejudice did not substantially outweigh its probative value. 

Mr. Gantt's testimony about the uncharged robberies

provided significant background information bolstering the 

charged conspiracy's plausibility, and the risk of prejudice 

attending such evidence was mitigated by the opportunity 

for cross-examination and by the District Court's limiting 

instruction. Thus, we hold that the District Court did not 

abuse its discretion by declining to exclude Mr. Gantt's 

testimony. 

B. Evidence of Photographic Identification 

Before trial, the District Court conducted an evidentiary 

hearing to determine the admissibility of testimony from 

Sergeant Gubbei stating that he saw Mr. Mathis exit the 

Jeep on October 14, 1998, and that he selected Mr. 

Mathis's picture from a photographic array on October 15, 

1998. At that hearing, Sergeant Gubbei testified that he 

chose Mr. Mathis's photograph from an array of eight 

photographs at the Maple Shade police department, and 

Mr. Mathis moved to exclude such testimony because 

Sergeant Gubbei had previously seen an identical 

_________________________________________________________________ 

McCormick on Evidence 662-63 (John W. Strong ed., 5th ed. 1999) 

("Much more is demanded than the mere repeated commission of crimes 

of the same class, such as repeated murders, robberies, or rapes. The 

pattern and characteristics must be so unusual and distinctive as to be 

like a signature.") (footnotes omitted). On this point, Mr. Gantt's 

testimony indicated only that all of the uncharged robberies at issue 

occurred near Camden, New Jersey, within approximately four months of 

one another, and that the robbers wore gloves and masks. Mr. Gantt 

further testified that sometimes his girlfriend waited outside the target 

bank in a car, other times she did not; sometimes one robber acted as 

an armed guard near the bank's door, sometimes not; sometimes the 

robbers would use a stolen getaway car, other times not; sometimes they 

used a .45 caliber handgun, other times a .22 caliber handgun, and 

sometimes they used toy guns or screwdrivers taped to look like guns. 

None of the authorities cited by the government has approved modus 

operandi admissibility based on such inconsistent and generally nondistinctive characteristics, and we find the evidence in this case 

insufficient to support such a theory. 

 10 
photograph of Mr. Mathis. Specifically, a Maple Shade 

detective had, roughly one month before the robbery, given 

Sergeant Gubbei materials describing various bank robbery 

suspects. According to Sergeant Gubbei, these materials 

included between thirteen and fifteen pages with 

approximately seven photographs of bank robbery suspects, 

and one of these photographs--virtually identical to that 

later placed in the array--depicted Mr. Mathis. 3 

Mr. Mathis argued that admitting this testimony from 

Sergeant Gubbei would violate the Due Process Clause's 

protection against certain suggestive identification 

procedures. In particular, Neil v. Biggers, 409 U.S. 188 

(1972), held that, for out-of-court identifications, 

"convictions based on eye-witness identification . . . will be 

set aside only if the photographic identification was so 

impermissibly suggestive as to give rise to a very 

substantial likelihood of . . . misidentification." Id. at 196- 

97 (internal quotation omitted).4 Biggers further declared 

that likelihood of misidentification should be measured by 

a totality of circumstances including: the witness's initial 

opportunity to view the suspect at the crime scene and 

degree of attention at that time, the witness's level of 

certainty in the disputed identification, the length of time 

between initial viewing and disputed identification, and the 

accuracy of any intervening description of the suspect 

occurring between those two events. Id. at 199-200.

In the present case, Mr. Mathis contended that "the very 

fact of [a] previous viewing" was itself sufficient to establish 

the identification procedure's suggestiveness. He further 

argued that a substantial likelihood of misidentification 

arose both from Sergeant Gubbei's limited opportunity to 

view Mr. Mathis as he fled and from Sergeant Gubbei's 

_________________________________________________________________ 

3. We base much of our analysis on Sergeant Gubbei's testimony 

because the materials themselves, aside from the page containing Mr. 

Mathis's picture, apparently were not introduced into evidence. 

4. See also United States v. Emanuele, 51 F.3d 1123, 1128 (3d Cir. 1995) 

(interpreting later cases as requiring only a "substantial risk of 

misidentification"). 

 11 
degree of attention, which was arguably impaired by other 

people and events he witnessed at that time.5 

The government replied that Sergeant Gubbei's testimony 

showed that he had only reviewed the materials containing 

Mr. Mathis's photograph once or twice, immediately after 

receiving them approximately a month before the Sun

National Bank robbery. Furthermore, Sergeant Gubbei

stated he had attended most closely to the suspects' modi 

operandorum, not to their photographs. The government 

also noted that Sergeant Gubbei described his view of Mr. 

Mathis's face on October 14 as unobstructed and clear, and 

that he exhibited both a high degree of attention in 

watching the Jeep's occupants disembark and a high level 

of certainty in making his subsequent photographic 

identification. 

In denying Mr. Mathis's motion to exclude the testimony, 

the District Court followed this court's two-step process for 

applying Biggers: 

 The first question is whether the initial identification 

 procedure was `unnecessarily' . . . suggestive. This 

 inquiry . . . contains two component parts: that 

 concerning the suggestiveness of the identification, and 

 that concerning whether there was some good reason 

 for the failure to resort to less suggestive procedures. If 

 a procedure is found . . . unnecessarily suggestive, the 

 next question is whether the procedure . . . gave rise to 

 such a `substantial likelihood of . . . misidentification' 

 that admitting the identification would be a denial of 

 due process. 

United States v. Stevens, 935 F.2d 1380, 1389 (3d Cir. 

1991) (internal quotation omitted). The District Court ruled 

that Mr. Mathis did not "initially demonstrate[that] the 

identification was impermissibly suggestive"; the District 

Court then proceeded to find that Sergeant Gubbei's

identification was reliably based in fact and most likely did 

_________________________________________________________________ 

5. Mr. Mathis conceded that Biggers's"length of time" factor weighed in 

favor of admitting the evidence, since the contested identification 

occurred just one day after Sergeant Gubbei viewed the Jeep's 

passenger. 

 12 
not result from impermissible suggestion. The District 

Court also found that the "background of the photo of the 

defendant is no darker or lighter than the other photos," 

that the cropped pictures did not reveal any difference in 

the subjects' build, and that the eight men "have the same 

skin tone, have the same facial features, eyes, nose, lip 

shape, [and] facial hair." 

We review the District Court's decision for abuse of 

discretion, applying clear error review to its underlying 

factual findings and plenary review to its conclusions 

drawn from such facts. United States v. Emanuele , 51 F.3d 

1123, 1127 (3d Cir. 1995); see also Sumner v. Mata, 455 

U.S. 591, 597 (1982) (discussing the relationship between 

fact and law in the context of pretrial identifications). On 

appeal, both parties have primarily disputed the factual 

reliability of Sergeant Gubbei's identification and whether 

there existed a substantial likelihood of misidentification. 

We affirm, however, based solely on the first part of the 

Stevens test, i.e., the District Court's determination that 

Mr. Mathis did not show the photographic identification to 

be unnecessarily suggestive. See United States v. Hill, 967 

F.2d 226, 230 (6th Cir. 1992) (noting the defendant's 

burden of proof on this issue). 

Mr. Mathis contends, as he did before the District Court, 

that "a photographic array created for purposes of a bank 

robbery investigation--which consists of seven photos the 

witness has never seen before, and one photo the witness 

has seen before in the very context of a bank robbery 

investigation--is by its very nature unduly suggestive." 

Appellant's Br. at 14. We disagree, finding that, without 

more, this allegation speaks only to the weight of the 

evidence and, thus, may properly be argued to the jury--as 

Mr. Mathis did in this case. Cf. Manson v. Braithwaite, 432 

U.S. 98, 116 (1977) ("[E]vidence with some element of 

untrustworthiness is customary grist for the jury mill. 

Juries are not so susceptible that they cannot measure 

intelligently the weight of identification testimony that has 

some questionable feature."). The unadorned fact that 

Sergeant Gubbei briefly viewed Mr. Mathis's picture, as part 

of a collection of materials distributed one month before the 

robbery, does not demonstrate sufficient suggestiveness to 

 13 
require constitutional inquiry into whether a 

misidentification might have occurred in this case.

Since we have not discovered cases squarely addressing 

facts like these, we are primarily guided by principles 

articulated in Stevens, 935 F.2d at 1380, where the

defendant's picture was selected from a photographic array 

by two witnesses who had previously identified the 

defendant from a police station's wanted board. That board, 

to which the witnesses were directed by a police officer as 

they filed their complaint, contained eight posters."[F]ive 

were composite sketches, one contained eight small 

photographs, and the other two were both photographs of 

[the defendant]. . . . [O]ne of his photographs was in color, 

whereas the other nine photographs were in black and 

white." Id. at 1388. In evaluating the suggestiveness of the 

board's collection of photographs, we acknowledged that 

the wanted board had "several suggestive attributes": 

"Whereas the posters of Stevens each contained 

photographs, most of the other posters had only composite 

sketches. Stevens's picture, moreover, was the only one 

that appeared twice . . . . Even more bothersome . .. are 

that Stevens's photographs were significantly larger than 

the others, and that Stevens was the only suspect 

portrayed in color." Id. at 1390. Each of these features 

"quite possibly could have drawn the victims' attention to 

Stevens" independent of the witnesses' recollection. Id. But 

we also noted certain considerations that counseled against 

deeming such suggestiveness "unnecessary," including the 

fact that the wanted board had not been "arranged with 

this particular crime in mind. It was, rather, a collection of 

random sketches and photographs that had been 

assembled in order to facilitate chance identifications . . . ." 

Id. Measured against this general law enforcement purpose, 

we also noted that wanted boards often cannot be made 

with photographs of uniform size. Thus, although aspects 

of the particular wanted board in Stevens were 

unnecessarily suggestive, we made significant efforts to 

stress that such displays generally are not so. Compare id. 

with id. at 1390 n.12. 

Here, the materials that Sergeant Gubbei received were 

apparently assembled for a law enforcement purpose whose 

 14 
validity is not challenged. Such materials obviously were 

not prepared or circulated with the Sun National Bank 

robbery (which occurred thereafter) in mind, nor, it seems, 

with awareness of influencing any photographic 

identification procedures. Cf. Emanuele, 51 F.3d at 1129 

("[W]e expressly do not require defendant to establish the 

government's state of mind. On the other hand, evidence 

that the government intended and arranged such [a 

potentially suggestive] encounter would be a substantial 

factor in the court's analysis."). We hold that, with respect 

to the present facts, due process does not protect 

defendants like Mr. Mathis from photographic materials 

briefly viewed one month before the disputed identification, 

when such materials are distributed only for purposes of 

general law enforcement. The brief time that elapsed 

between Sergeant Gubbei's receiving the materials and his 

selecting Mr. Mathis's picture from the photographic array 

significantly reduces the level of cognizable "suggestiveness" 

at issue. And though it might seem preferable, or even more 

effective, for police departments to use photographs in 

identification arrays that are different from those used in 

previously distributed suspect data, we do not find an 

identification "unnecessarily suggestive" simply because the 

same photograph, or a very similar photograph, is used in 

both. Law enforcement agencies commonly lack an 

abundance of particular suspects' photographs for use in 

assembling photographic arrays. And even where various 

pictures are on hand, lists are not often kept recording 

which pictures have been circulated to officers who later 

happen to be eyewitnesses. Given such operational 

circumstances--similar to those concerning police station 

wanted boards--we cannot agree that Sergeant Gubbei's 

prior exposure to Mr. Mathis's photograph, in and of itself, 

renders his subsequent identification unnecessarily

suggestive. 

Mr. Mathis further claims that certain "additional 

circumstances" aggravated the suggestiveness of Sergeant 

Gubbei's photographic identification. First, Mr. Mathis 

notes that Sergeant Gubbei chose Mr. Mathis's photograph 

only after Mr. Gantt had already identified one of his coconspirators by name as "Mr. Mathis." We agree with the 

government, however, that there is no evidence to connect 

 15 
Mr. Gantt's identification of Mr. Mathis by name with 

Sergeant Gubbei's identification of Mr. Mathis by image. 

Since the photographic array did not list the names of its 

subjects, Mr. Mathis has failed to show how Mr. Gantt's 

prior identification by name increased the photographic 

array's suggestiveness. Second, Mr. Mathis claims that, of 

the eight photographs in the array, Mr. Mathis's picture 

"quite obviously" was the only one of a "slender and slight" 

build. We review for clear error the District Court's factual 

finding to the contrary, and we find none. The array at 

issue portrays only the subjects' heads and necks, making 

their general physiques very difficult to estimate. Even from 

this limited view, however, it seems that at least two other 

photographs depict men of a build similar to Mr. Mathis's. 

Third, Mr. Mathis claims that the background of Mr.

Mathis's photograph "was noticeably darker than the

remaining seven." Upon reviewing the array, we agree and 

find the District Court's finding to the contrary clearly 

erroneous; thus, we must assess the impact of this 

circumstance on the alleged "unnecessary suggestiveness" 

of Sergeant Gubbei's identification. Although Mr. Mathis's 

picture is darker than the others in the array, there are at 

least three other pictures whose backgrounds are 

somewhat dark. Given the current technological state of 

photographic reproduction, and the variety of backgrounds 

evident in the eight pictures at issue, we hold that the 

slightly darker background of Mr. Mathis's picture did not 

significantly contribute to the array's unnecessary

suggestiveness. See United States v. Burdeau, 168 F.3d 

352, 357 (9th Cir. 1999). 

In sum, we find that Sergeant Gubbei's photographic

identification was not "unnecessarily suggestive" to the 

degree required by Biggers. Due process does not mandate 

the removal of testimony like Sergeant Gubbei's from the 

jury's consideration, even if such evidence presents (as 

much admissible evidence does) a risk of misidentification. 

On the contrary, such modest levels of "suggestiveness," 

which are not deemed constitutionally "unnecessary," 

speak only to the evidence's ultimate reliability and should 

therefore be argued for authoritative appraisal to the 

factfinder. On the current record, we find no abuse of 

 16 
discretion in the District Court's decision to admit Sergeant 

Gubbei's testimony into evidence. 

C. Expert Testimony Regarding Eyewitnesses 

After the government had presented its witnesses, Mr. 

Mathis sought to present testimony from Dr. Geoffrey 

Loftus regarding the reliability of eyewitness identifications 

such as Sergeant Gubbei's. The District Court conducted 

an evidentiary hearing to determine whether such 

testimony was admissible. During that hearing, Dr. Loftus 

testified that he had received a doctoral degree from 

Samford University in clinical psychology and had served as 

a professor at the University of Washington for over twentyfive years. His doctoral dissertation concerned humans' 

ability to recall and recognize pictures from memory, and 

his subsequent studies in the field of human perception 

and scientific methodology were published as books and 

professional journal articles. Based on these and other 

academic credentials, the District Court qualified Dr. Loftus 

as an expert in the field of human perception and memory. 

Dr. Loftus then proffered testimony on four topics 

concerning the operation of human memory: (i) the 

preconditions for forming accurate memories, (ii) the 

confounding impact of "double identification" or "post-event 

information," (iii) the relationship between individuals' 

confidence in describing memories and the accuracy of 

such memories, and (iv) potential disruptions caused by 

"weapons focus." With respect to memory formation, Dr. 

Loftus observed that, among other circumstances, the 

brevity of one's visual exposure to an object tends to cause 

an incomplete memory, which might later be especially 

susceptible to biasing influences. Dr. Loftus described 

"double identification" as a problem in determining whether 

one's memory derives from one of two or more possible 

visual exposures to an object. According to Dr. Loftus, a 

witness's recognizing someone, under circumstances 

similar to those described by Sergeant Gubbei, could derive 

either from the witness's actually having seen the 

recognized person or from a previous exposure to that 

person's photograph. Dr. Loftus indicated, citing scientific 

studies, that when one encounters a remembered image 

along with "post-event information" suggesting a particular 

 17 
context from which the image might be remembered (such 

as the Sun National Bank robbery's photographic array), 

such post-event information can become incorporated with 

the original memory, creating an inaccurately 

"remembered" association between the image and its 

source. Regarding witnesses' confidence in their 

identifications, Dr. Loftus stated that "the correspondence 

between confidence and accuracy is, at best, about 25 

percent." He further explained that when conditions

attending the recalled memories are poor, "when, for 

example, there is only a brief duration . . . [or] incorrect 

post-event information introduced to the [observer], it's 

under those circumstances that the relation between

confidence and [accurate] memory is zero." And on the topic 

of "weapons focus," Dr. Loftus discussed studies finding 

that the presence of a dangerous weapon can weaken one's 

ability to recall other aspects of a remembered scene, 

including individuals present therein. 

In applying these principles to hypothetical questions 

intended to simulate the facts of this case, Dr. Loftus stated 

that "it's two to three times as likely that the identification 

in the photo montage was made based on seeing the 

photograph four weeks earlier than it was based on seeing 

the individual" who fled on October 14, 1998. Dr. Loftus 

also concluded that, if the photo array did not actually 

depict the person who exited the Jeep, that array itself 

would constitute incorrect post-event information. And 

such misinformation might have caused Sergeant Gubbei's 

identification of Mr. Mathis to reflect the man seen in the 

previously viewed photograph, who was observed under 

conditions favorable to memory formation, rather than the 

man seen running away, who was observed under 

conditions unfavorable to memory formation. Dr. Loftus 

further opined that the officer's confidence in this 

identification and the factual accuracy thereof would have 

a probabilistic relationship of "essentially zero" under such 

circumstances. 

Mr. Mathis moved to admit the foregoing testimony into 

evidence pursuant to Federal Rule of Evidence 702, which 

provides: 

 18 
 If scientific, technical, or other specialized knowledge 

 will assist the trier of fact to understand the evidence 

 or to determine a fact in issue, a witness qualified as 

 an expert . . . may testify thereto in the form of an 

 opinion or otherwise, if (1) the testimony is based upon 

 sufficient facts or data, (2) the testimony is the product 

 of reliable principles and methods, and (3) the witness 

 has applied the principles and methods reliably to the 

 facts of the case. 

Fed. R. Evid. 702. In particular, Mr. Mathis argued that Dr. 

Loftus's testimony was based on generally accepted 

scientific methods and data, that there was a direct relation 

between the proffered testimony and the factual issues in 

dispute, and that the proffered testimony would"refute 

common assumptions about the reliability of eye witness 

identification testimony that will assist the jury to weigh 

the credibility of Sergeant Gubbei's eye witness 

identification." 

The District Court excluded Dr. Loftus's testimony, but it 

ratified Dr. Loftus's qualifications as an expert and 

dismissed all methodological challenges to the studies he 

cited. The following constitutes the District Court's 

explanation of its ruling: 

 I'm particularly concerned with [Rule] 403 and I'm 

 inclined not to allow this testimony. I believe this 

 testimony has the probability of confusing and 

 misleading the jury. I find no problem with his 

 qualifications. Obviously he is qualified in this area. 

 The debate over the differences in the studies is an 

 interesting academic debate. As [defense counsel] 

 points out, however, there is only one [w]ay to run the 

 studies. You can't run them in a live situation, they 

 have to be in a controlled situation. That does not give 

 me pause. 

 What does give me pause is the fact that I believe that 

 in point of fact, there is a probability that there will be 

 unfair prejudice here. The aura of reliability that's 

 attached to an expert witness, I believe, is significant. 

 Listening to this expert, it seems to me, that the 

 testimony itself has the potential, if not controlling 

 19 
 probability of confusing the jury. There is no issue in 

 this case about cross-racial identification. There is no 

 issue about stress. They were the two more compelling 

 issues about which I was concerned. 

 The issues concerning the focus at the time of the 

 chase and when the defendant exited the vehicle are 

 subject to the jury. The defense in this case had an 

 untrammeled opportunity to cross and did, in fact, 

 cross the police officer vigorously on that area. The 

 testimony is, I think clear. Whether the jury accepts it 

 or not, how the jury accepts it is clearly within their 

 province. I do not see how this evidence will do 

 anything, other than to confuse and mislead the jury. 

 I decline the invitation to admit. 

1. Admissibility of Dr. Loftuss Testimony 

We review the District Court's decision to exclude Dr. 

Loftus's testimony for abuse of discretion. General Electric 

Co. v. Joiner, 522 U.S. 136, 143 (1997); Oddi v. Ford Motor 

Corp., 234 F.3d 136, 146 (3d Cir. 2000). Although the 

District Court explicitly rested its decision on Rule 403's 

standards for probative value and prejudice, the 

government on appeal invokes only Rule 702's prescriptions 

regarding expert testimony. We will address both rules, 

beginning with Rule 702. 

This court has construed Rule 702 as embodying "three 

distinct substantive restrictions on the admission of expert 

testimony: qualifications, reliability, and fit." Elcock v. 

Kmart Corp., 233 F.3d 734, 741 (3d Cir. 2000). Only "fit" is 

contested here; the government acknowledges that Dr. 

Loftus is a properly qualified expert and that his methods, 

principles, and data are of a sufficiently reliable scientific 

character. See generally Daubert v. Merrell Dow Pharm., 

509 U.S. 579, 592-94 (1993) (discussing factors that may 

be considered in assessing scientific reliability); In re Paoli 

R.R. Yard PCB Litig., 35 F.3d 717, 742 n.8 (3d Cir. 1994) 

(same). 

Rule 702's fit requirement derives from the textual

provision that "scientific, technical, or other specialized 

knowledge will assist the trier of fact to understand the 

evidence or to determine a fact in issue." Fed. R. Evid. 702. 

 20 
The requirement is "not intended to be a high one,"

however, Oddi, 234 F.3d at 145, and its principle is not 

dissimilar to the Federal Rules' general provision that, 

unless otherwise specified, "[a]ll relevant evidence is 

admissible" and "[e]vidence which is not relevant is not 

admissible." Fed. R. Evid. 402; Kumho Tire Co. v. 

Carmichael, 526 U.S. 137 (1999) (interpreting Rule 702 as 

requiring all expert testimony to be relevant and reliable). 

Compare United States v. Downing, 753 F.2d 1224, 1230 

(3d Cir. 1985) (noting "the liberal standard of admissibility 

mandated by Rule 702"), with Daubert, 509 U.S. at 587 

(noting that Rule 402's "basic standard of relevance is a 

liberal one"). See generally Daubert, 509 U.S. at 592 

(describing inquiry under Rule 702 as a determination "of 

whether the reasoning or methodology underlying the

testimony is scientifically valid and of whether that 

reasoning or methodology properly can be applied to the 

facts in issue"). 

The clearest guide for interpreting Rule 702 in the

context of this case is United States v. Downing , 753 F.2d 

at 1226, wherein this court, in 1985, first considered the 

admissibility of expert testimony concerning human 

memory and eyewitness testimony. In Downing, we 

discussed certain of the rationales advanced by other 

courts of appeals in prior years for excluding such

testimony, including notions that relevant issues could 

adequately be raised through cross-examination and 

common sense, that such testimony usurps the jury's

function, and that such evidence would lead to an unduly 

confusing "battle" of experts. Id. at 1229-30 & n.4. In 

explaining why we found those rationales unpersuasive, we 

disavowed skepticism of such testimony as a matter of 

principle, and we remanded for the district court to apply 

Rule 702's "helpfulness test." We described this test, in 

pertinent part, as follows: "[A]dmission depends upon the 

`fit,' i.e., upon a specific proffer showing that scientific 

research has established that particular features of the 

eyewitness identifications involved may have impaired the 

accuracy of those identifications." Id. at 1226. 

In the case at bar, the government challenges the fit of 

Dr. Loftus's testimony in three respects. First, on the 

 21 
subject of "double identification" and "post-event 

information," the government claims that Dr. Loftus's 

testimony did not pertain to the present facts because, 

according to Dr. Loftus's own theory, Sergeant Gubbei 

viewed Mr. Mathis's face only once, as part of the suspect 

materials, before selecting from the photographic array. 

Thus, the government claims, this case did not involve any 

"double" identification. Appellee Br. at 36. The government 

also argues that there was no post-event information 

"between the visual identification of Mathis on the day of 

the robbery and the photo array identification." Id. at 38. 

Each of these arguments misconstrues the substance of Dr. 

Loftus's testimony. As explained supra, double 

identification theory indicates that a person confronting an 

image may have a firm memory of having previously viewed 

the image, but may not have a similarly firm memory of 

when that viewing occurred. Given the suboptimal 

conditions for memory formation during the Jeep incident, 

and given the relative calm under which Sergeant Gubbei 

had previously seen a photograph of Mr. Mathis, Dr. Loftus 

testified that Sergeant Gubbei might have recalled Mr. 

Mathis's face from that previously viewed photograph 

but--because he was searching the photographic array in 

order to identify the Jeep's passenger--he might have 

wrongly associated the recalled photographic image with 

the fleeing robbery suspect. Contrary to the government's 

misunderstanding, the two pertinent "identifications" were 

the view of the suspect materials and the view of the man 

who fled. 

Furthermore, according to Dr. Loftus, the photographic 

array constituted potentially inaccurate post-event

information, which might have influenced Sergeant Gubbei 

wrongly to associate Mr. Mathis's image with the Sun 

National Robbery.6 Dr. Loftus also was of the view that 

_________________________________________________________________ 

6. The government argues that the photographic array was not distortive 

post-event information if, as we have now held, the array was not 

unconstitutionally suggestive. As our earlier discussion makes clear, 

however, the standards of "unnecessary suggestiveness" for admissibility 

under Biggers simply have no bearing on Dr. Loftus's testimony. A 

photographic identification may be highly suggestive as a psychological 

matter and still be deemed legally admissible as a constitutional one. A 

determination that such an identification is admissible poses no greater 

barrier to attack by expert testimony than it does to cross-examination. 

 22 
Sergeant Gubbei's act of choosing Mr. Mathis's photograph 

from the several photographs constituting the photo array 

was itself post-event information that could have influenced 

Sergeant Gubbei's face-to-face identification of Mr. Mathis 

at trial. Dr. Loftus argued that these pieces of post-event 

information may have distorted each of Sergeant Gubbei's 

purported identifications of Mr. Mathis. Given the close 

correspondence between these aspects of Dr. Loftus's 

testimony and the factual issues disputed at trial, we 

conclude that the proffered evidence did not lack 

evidentiary fit for purposes of Rule 702. 

Second, the government contends that Dr. Loftus's 

observations with respect to the weak relationship between 

an eyewitness's testimonial confidence and the accuracy of 

such testimony did not fit because, in the government's 

view, Dr. Loftus presented "nothing more than a general 

thesis on the correlation between confidence and accuracy." 

Id. at 44. As an initial matter, this characterization of the 

evidence appears mistaken. Dr. Loftus testified about the 

relationship between confidence and accuracy under 

specific circumstances similar to those in this case: an 

identification based on a brief view, in the presence of a 

deadly weapon, and several potentially distracting events 

on-going. Also, Sergeant Gubbei's testimony on direct 

examination indirectly implicated his confidence as an 

element supporting the credibility of his identification. In 

describing how he selected Mr. Mathis's photograph,

Sergeant Gubbei was asked, "Q: Did you have any 

hesitation in determining those individuals [Mr. Mathis and 

Mr. Gantt]? A: No, I didn't." Later, after already having 

described his choice of Mr. Mathis's photograph from the 

array, Sergeant Gubbei was again asked, "Q: Sitting here 

today Sergeant, was your identification of Keith Mathis 

from the photo array based upon your viewing him the day 

before, following the bank robbery or on the photograph 

that you had been shown in the packet? A: I identified him 

from the incident that took place from the Sun National on 

the day before." The level of confidence underlying Sergeant 

Gubbei's identification came into more explicit focus during 

cross-examination: 

 Q: [A]s we sit here today, is it even possible that the 

 identification you made of Mr. Mathis in that photo 

 23 
 array was based not on seeing him exiting that Jeep 

 but on the previous opportunity to observe that 

 photograph. 

 A: No, I'm positive by him getting out of the vehicle 

 . . . . 

 Q: Your answer is it's not even a possibility? 

 A: I guess there is a remote possibility, but I'm positive 

 of the identification when he exited the vehicle. 

Where Sergeant Gubbei testified so directly regarding his 

high confidence in the disputed identification, it seems 

clear that Dr. Loftus's testimony did address, for purposes 

of Rule 702, pertinent factual disputes in the case. See 

Stevens, 935 F.2d at 1400 (reaching an identical conclusion 

where the defendant sought "[t]o rebut the natural 

assumption that [the witnesses'] strong expression of 

confidence indicates an unusually reliable identification"). 

Third, the government argues that Dr. Loftus's opinions 

about "weapons focus" were not relevant to the present 

case because Sergeant Gubbei was a police officer who was 

quite accustomed to firearms, and because the relevant gun 

was pointed into the air, not at Sergeant Gubbei. Such 

arguments may be useful topics for cross-examination, but 

we do not find them persuasive grounds for exclusion 

under Rule 702. Dr. Loftus expressed the view that the 

phenomenon of weapons focus derives both from the 

infrequency with which most individuals view deadly

weapons and from a survival instinct that draws one's 

attention to potentially threatening objects. He pointed out 

that various studies, performed by him and by other

scientists, showed that a weapon's presence in a scene 

substantially affects subjects' ability to recall individuals in 

that scene. He further pointed out that close physical 

proximity of a weapon to another object (e.g. , the face of the 

Jeep's passenger) would not appreciably reduce the 

weapon's distortive influence on a witness's memory. 

With respect to Sergeant Gubbei's being a police officer, 

Dr. Loftus acknowledged that one's degree of familiarity or 

unfamiliarity with the weapon at issue generally would 

affect the practical impact of weapons focus. But Dr. Loftus 

 24 
also noted that the primary study on which he relied 

involved a knife, which, in his view, was an adequately 

familiar object for most people. Moreover, Dr. Loftus 

specifically rejected any notion that police officers would be 

immune to the psychological principles he described. With 

respect to the particular location of the gun, Dr. Loftus 

indicated that psychological studies inevitably take place in 

secure environments; thus, all of the cited studies assumed 

observers who were actually safe from the weapon at issue. 

He observed that the "survival" impetus for weapons focus 

would, in real life situations, likely be even higher than the 

cited studies indicated. Thus, we cannot agree with the 

government's suggestion that Dr. Loftus's expert opinions 

regarding weapons focus were not relevant for purposes of 

Rule 702. 

Having concluded that the government's arguments for 

exclusion under Rule 702 cannot succeed, we turn now to 

Rule 403. As an initial matter, "[w]e are mindful that a trial 

court is in a far better position than an appellate court to 

strike the sensitive balance dictated by Rule 403. When a 

trial court engages in such a balancing process and

articulates on the record the rationale for its conclusion, its 

conclusion should rarely be disturbed." Pinney, 967 F.2d at 

918; see also Downing, 753 F.2d at 1242-43 (noting Rule 

403's important role in assessing whether expert 

testimony's probative value is "substantially outweighed by 

other dangers, e.g., confusion of the issue or waste of 

time"). But when a district court does not explain its ruling, 

and no adequate explanation can be gleaned from the

record, appellate courts often have little choice but to 

undertake such evaluation themselves. See e.g. , United 

States v. Murray, 103 F.3d 310, 319 (3d Cir. 1997) (noting 

that when district courts fail to explain their rulings under 

Rule 403, "we are able to perform this balancing here, 

[though] other cases may require remand . . . or even . . . 

a new trial"); United States v. Himelwright , 42 F.3d 777, 

785 (3d Cir. 1994). 

We find it difficult to accord the customary degree of 

deference to the District Court's discretion in this case 

because the District Court explained its ruling with little 

more than a series of conclusions: 

 25 
 [T]his testimony has the probability of confusing and 

 misleading the jury. . . . [T]here is a probability that 

 there will be unfair prejudice here. The aura of 

 reliability that's attached to an expert witness, I 

 believe, is significant. Listening to this expert, it seems 

 to me, that the testimony itself has the potential, if not 

 controlling probability of confusing the jury. . . . 

 [Sergeant Gubbei's] testimony is, I think, clear. 

 Whether the jury accepts it or not, how the jury 

 accepts it is clearly within their province. I do not see 

 how this evidence will do anything, other than to 

 confuse and mislead the jury. 

The District Court clearly expressed concern with"[t]he 

aura of reliability that's attached to an expert 

witness"--which is one reason for district courts' 

"gatekeeping function" in assessing expert testimony under 

Rule 702. See Daubert, 509 U.S. at 592, 594. There is no 

suggestion, however, that such an aura of reliability was 

unwarranted in this case or, to be more precise, that it was 

unfairly prejudicial. From the record, it seems that Dr. 

Loftus was an extremely qualified, experienced academic 

presenting opinions on topics near the heart of his

expertise. Moreover, Dr. Loftus's conclusions seem closely 

tied to empirical studies whose reliability is not impeached, 

and he explained the bases for these studies at apparently 

appropriate length. In short, we see no reason to believe 

that Dr. Loftus's aura of reliability reflected anything other 

than his actual reliability as an expert witness. With 

respect to the District Court's concern with "confusing and 

misleading the jury" and "unfair prejudice," we are unable 

to discern from these references, any more than from our 

own review of the record, how such problems might arise. 

The government's oral argument before the District Court 

also fails to reveal any valid basis for exclusion under Rule 

403. The government focused on two contentions. First, it 

claimed that the studies cited by Dr. Loftus did not 

sufficiently match the circumstances of this case. The 

District Court rejected this position, holding that such 

disputes "did not give [him] pause," and the government 

has conceded this issue on appeal. 

Second, the government stated that: 

 26 
 [T]he problem that bothers me most, your Honor, is the 

 danger of overwhelming the jury. When we gave this 

 witness a hypothetical that was slightly--you know, 

 everyone in this courtroom knows the facts better than 

 I do, but [it] sounded to me slightly tinged toward the 

 defense version of the offense, the witness stated as a 

 fact that the sergeant would not remember accurately. 

 When I gave him the version that was a little bit closer 

 to what I believe the facts to be and the Government 

 version, he stated as a fact that his conclusion would 

 be very different under those facts. So what he's doing 

 is telling the jury the answer instead of allowing the 

 jury to determine the facts for themselves. Any 

 hypothetical that sets forth those facts is likely to have 

 a serious effect on the jury's memory of the testimony 

 rather than allowing the jury to decide what the jury's 

 going to decide. 

The full significance of this language is not clear. In part, 

the objection apparently derives from the fact that Dr. 

Loftus's answers regarding Sergeant Gubbei's memory

changed when the hypotheses under consideration were 

altered regarding, for example, the number of seconds 

Sergeant Gubbei saw the fleeing man's face and the 

attention Sergeant Gubbei paid to the distributed suspect 

materials. Some might view such a change in an expert's 

analysis as the reward of a successful cross-examination; it 

seems hard to view such variation as a basis for excluding 

the testimony under Rule 403. The government did not 

demonstrate, and has not done so now, how this dimension 

of Dr. Loftus's testimony tended to cause any articulable 

degree of unfair prejudice, confusion, or delay. 

Another aspect of the government's objection stems from 

a concern, which the District Court seemingly shared, that 

Dr. Loftus's testimony might usurp the jury's function. 

Insofar as this argument constitutes a general attack on 

expert testimony concerning eyewitness identifications, 

such issues are largely resolved by Downing. See id. at 

1229-30 & n.4. Similar to other types of expert witnesses, 

who might testify about the flaws of a computerized filing 

system or the proper interpretation of satellite photographs, 

experts who apply reliable scientific expertise to juridically 

 27 
pertinent aspects of the human mind and body should

generally, absent explicable reasons to the contrary, be 

welcomed by federal courts, not turned away. Cf. United 

States v. Smithers, 212 F.3d 306, 311-12 & n.1 (6th Cir. 

2000) (describing a judicial trend toward, and an 

empirically supported need for, accepting expert testimony 

about eyewitness identification). In this case, Dr. Loftus 

made quite clear that he did not intend to tell the jury 

whether Sergeant Gubbei was lying or telling the truth. Like 

more typical sorts of expert witnesses, Dr. Loftus attempted 

to provide information that, if itself deemed credible, might 

cause the jury to evaluate Sergeant Gubbei's testimony in 

a different light. 

In analyzing for ourselves whether the four components 

of Dr. Loftus's testimony7 were admissible, we follow 

standards set forth in United States v. Stevens , which is 

also discussed supra in Part II.B. In Stevens, the defendant 

proffered expert testimony on six topics: "(1) the accuracy of 

cross-racial identifications; (2) the effect of weapon focus on 

identifications; (3) the effect of stress on identifications; (4) 

the suggestiveness of the wanted board [from which the 

defendant was initially identified]; (5) the relation back of 

subsequent identifications to the initial identification; and 

(6) the lack of correlation between confidence and accuracy 

in eyewitness identifications." 935 F.2d at 1397. The 

district court permitted expert testimony on the first three, 

but excluded testimony on the remainder. 

On appeal, the Stevens court affirmed the exclusion of 

proffered testimony regarding the wanted board's 

"suggestiveness," in deference to the district court's 

determination that " `[t]he fact that there are two pictures 

. . . of the same person and one [is] in color, I think[,] . . 

. is certainly apparent [to] the jury . . . for the jury to make 

its own determination.' " Id. at 1399; cf. United States v. 

Gibbs, 190 F.3d 188, 212 (3d Cir. 1999) ("We have upheld 

the exclusion of expert testimony when that testimony 

ventures into areas in which the jury needs no aid or 

illumination."). Similarly, in this case, Dr. Loftus's 

_________________________________________________________________ 

7. Memory formation, double identification and post-event information, 

the relationship between confidence and accuracy, and weapons focus. 

 28 
testimony--claiming that more accurate memories are

produced by objects that are viewed for longer periods of 

time--is not the type of information that, in and of itself, 

would warrant exposition by an expert witness; thus, we 

concur in the District Court's decision to exclude such 

testimony under Rule 403.8 

Stevens's expert testimony regarding "relation back" 

apparently explained that "once a witness makes an 

identification, he or she will tend to stick with that initial 

choice at subsequent photographic arrays or lineups, even 

if it was erroneous." Stevens, 935 F.2d at 1399. Such 

evidence closely resembles the part of Dr. Loftus's

testimony on "double identification" and "post-event 

information" that explained how, after Sergeant Gubbei had 

already selected Mr. Mathis's picture from the array, his incourt identification was likely to be consistent therewith, 

regardless of any actual memory of the underlying events. 

In Stevens, we affirmed the exclusion of expert testimony 

on this topic because we found the testimony "rather 

pedestrian" and "susceptible of elucidation without

specialized knowledge." Id. at 1399-1400. We are bound to 

reach a parallel conclusion here; hence, we affirm the 

exclusion of Dr. Loftus's testimony on this subject. 

Another portion of Dr. Loftus's discussion of "double 

identification," however, was significantly more complex 

than the testimony at issue in Stevens. In particular, Dr. 

Loftus described studies in which subjects remembered 

having seen an image, but, upon being asked to associate 

that image with one of two times they might possibly have 

seen it, the subjects often "remembered" inaccurately. Dr. 

Loftus further explained how Sergeant Gubbei might have 

clearly remembered Mr. Mathis's face from having 

previously seen a photograph of Mr. Mathis, but might have 

confidently and incorrectly associated that memory with the 

_________________________________________________________________ 

8. We do not mean to bar, by this determination, the strong possibility 

that parts of Dr. Loftus's account of memory formation might have been 

properly admissible as a necessary precursor, or ancillary, to other 

admissible testimony regarding memory. Our ruling merely indicates 

that such testimony, in and of itself, does not necessarily surmount the 

barrier of Rule 403. 

 29 
previous day's fleeing suspect. Dr. Loftus indicated that 

such a misidentification was peculiarly likely in 

circumstances where one possible event-memory 

association (the previously viewed photograph) involved 

favorable conditions for memory formation and involved the 

same visual medium as the image to be identified (a

photograph), whereas the other event-memory association 

(the robbers' escape) involved unfavorable memory 

conditions and a different visual medium (threedimensional observation). We believe that testimony of this 

sort, with its accompanying level of scientific detail, would 

not simply duplicate jurors' intuitions or common sense, 

and such principles seem difficult to establish indirectly 

through cross-examination. Accordingly, we find that the 

District Court abused its discretion in excluding such 

testimony. 

The third type of testimony analyzed in Stevens 

concerned the relationship between an eyewitness's 

confidence and the accuracy of a resultant identification. 

Dr. Loftus opined on this same topic in the present case, 

stating that the correspondence between confidence and 

accuracy is "at best, about 25 percent" and, under 

circumstances like these, is "essentially zero." In Stevens, 

we held that such information was sufficiently illuminative 

and susceptible to scientific expertise that exclusion was 

unacceptable under "the liberal standard of admissibility of 

Rule 702" and Rule 403. Id. at 1400-01. In the present 

case, the government objects that Stevens cannot "mean 

that [any time] an eyewitness has confidence in his

identification, a defendant is automatically entitled to 

present testimony that confidence has little or no 

correlation to accuracy." Appellee's Br. at 43. We agree that 

Stevens did not establish such a universally applicable rule, 

and we also decline to do so here. As the government 

correctly notes, analysis under Rules 702 and 403 is factintensive and case-specific. That said, however, Stevens did 

hold that, when expert testimony of this character satisfies 

the reliability and fit requirements of Rule 702, and when 

there is no countervailing rationale for excluding the 

evidence under Rule 403, the evidence must be admitted. 

In light of our findings regarding this evidence's probative 

value and our inability to discover any offsetting prejudice, 

 30 
confusion, or delay, we hold that the District Court abused 

its discretion in failing to admit Dr. Loftus's testimony on 

the relationship between eyewitness confidence and 

accuracy. 

The final topic discussed by Dr. Loftus was "weapons 

focus." In Stevens, this issue was not before us because the 

District Court had admitted expert testimony on the

subject. In light of the principles decided in Stevens, as well 

as those discussed supra, we find that Dr. Loftus's

proposed testimony regarding weapons focus should have 

been admitted into evidence. The government argues that a 

jury does not need expert testimony to learn "the idea that 

one might be distracted by a weapon." Appellee's Br. at 34. 

But Dr. Loftus's testimony was not limited to such a narrow 

scope. In combination, the studies he discussed indicated 

that the presence of weapons weakened memories of other 

aspects of an observed scene, even when such weapons 

posed no immediate threat, and even when those weapons' 

images might be located quite near the object later to be 

identified. We find that the degree and scope of memory 

distortion that, according to Dr. Loftus, a weapon typically 

causes for eyewitnesses are not matters that would 

necessarily be apparent to jurors. And, just as with the 

other admissible aspects of Dr. Loftus's testimony, it is 

difficult to comprehend how weapons' destructive effect on 

memory might be elucidated through cross-examination. 

Especially if Dr. Loftus is correct that witnesses 

remain confident of their identifications even when those 

identifications are inaccurate, eyewitnesses cannot be 

expected--even under the most skilled 

questioning--explicitly to recall or nonverbally to reveal the 

extent to which their remembered impressions might have 

been distorted or undermined. We find that, in this case, 

and on this record, it was an abuse of discretion not to 

admit such testimony into evidence. 

D. Harmless Error 

Our final step is to consider whether the District Court's 

error in excluding parts of Dr. Loftus's testimony was 

legally harmless. See 28 U.S.C.A. S 2111 ("In the hearing of 

any appeal[,] . . . the court shall give judgment after an 

examination of the record without regard to errors or 

 31 
defects which do not affect the substantial rights of the 

parties."); Fed. R. Crim. P. 52(a); Fed. R. Evid. 103(a); 

Kotteakos v. United States, 328 U.S. 750 (1946). This court 

has held that a non-constitutional error committed at trial 

does not warrant reversal in circumstances where"it is 

highly probable that the error did not contribute to the 

judgment." United States v. Helbling, 209 F.3d 226, 241 (3d 

Cir. 2000) (internal quotation omitted). And the applicable 

standard for " `[h]igh probability' requires that we have a 

sure conviction that the error did not prejudice the 

defendants. We may not simply conclude that it is more 

likely than not that the error was harmless. On the other 

hand, we may be firmly convinced that the error was

harmless without disproving every `reasonable possibility' of 

prejudice." United States v. Jannotti, 729 F.2d 213, 220 n.2 

(3d Cir. 1984) (internal citations omitted). The burden of 

demonstrating such high probability lies with the 

government, United States v. Adams, 2001 WL 543711 at 

*4 (3d Cir. May 23, 2001), but we retain our established 

authority to affirm on any ground supported by the record, 

Nicini v. Morra, 212 F.3d 798, 805 (3d Cir. 2000) (en banc); 

Alexander Hamilton Life Ins. Co. of Am. v. Gov't of Virgin 

Islands, 757 F.2d 534, 547-58 (3d Cir. 1985). 

The government contends that, even if (as we now have 

found) the District Court wrongly failed to admit certain 

testimony from Dr. Loftus, Mr. Mathis's conviction should 

be affirmed because the government presented other 

evidence that constituted more "compelling evidence of 

Mathis's guilt than Sergeant Gubbei's identification." 

Appellee's Br. at 47. In particular, the government relies on 

testimony from Mr. Gantt, who described his cooperation 

with Mr. Mathis in robbing the Sun National Bank and 

eleven other banks. According to the government, Mr. 

Gantt's "tremendous opportunity to observe, speak to, and 

identify Mathis was damning and far outweighed Sergeant 

Gubbei's testimony in importance." Id. Mr. Mathis replies 

by challenging Mr. Gantt's credibility, both noting that Mr. 

Gantt lied to police after his arrest and arguing that Mr. 

Gantt's plea agreement provided a motive to lie if doing so 

might advance Mr. Mathis's prosecution. In Mr. Mathis's 

view, the government wrongly urges this court to"speculate 

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that the jury would have convicted defendant . . . had it 

. . . heard Dr. Loftus' testimony . . . . [T]he jury may well 

have concluded that the government had failed to bear its 

burden of proving beyond a reasonable doubt that . .. 

[Mathis] participated in the Sun National Bank robbery." 

Reply Br. at 23. In essence, the government asks this court, 

apparently as a matter of first instance, to weigh the import 

of Mr. Gantt's testimony against that of Sergeant Gubbei's 

testimony, while Mr. Mathis asks us not to "speculate" 

about what the jury would have done if Dr. Loftus had 

testified. 

We find that neither of these suggestions, viewed in 

isolation, is well-suited to our role in this appeal. As the 

Supreme Court held in Kotteakos: 

 [I]t is not the appellate court's function to determine 

 guilt or innocence. Nor is it to speculate upon probable 

 reconviction and decide according to how the

 speculation comes out. . . . Those judgments are 

 exclusively for the jury . . . . But this does not mean 

 that the appellate court can escape altogether taking 

 account of the outcome. . . . In criminal causes that 

 outcome is . . . . guilt in law, established by the 

 judgment of laymen. And the question is, not were they 

 right in their judgment . . . . It is rather what effect the 

 error had or reasonably may have had upon the jury's 

 decision. The crucial thing is the impact of the thing 

 done wrong on the minds of other men, not on one's 

 own, in the total setting. 

Kotteakos, 328 U.S. at 763-64. Our inquiry is not whether 

this court's members would convict Mr. Mathis on the 

evidence presented, or whether we would do so based on 

that evidence plus Dr. Loftus's wrongly excluded testimony. 

Rather, we begin with the guilty verdict the jury has already 

rendered, and we determine only whether, "after an 

examination of the record," 28 U.S.C.A. S 2111, "it is highly 

probable" that the jury would have reached the same

decision absent the identified error. Helbling , 209 F.3d at 

241. 

Although we believe that portions of Dr. Loftus's proffered 

testimony should have been admitted, we also find that, in 

 33 
the context of the record as a whole, his testimony was 

highly unlikely to have caused a different result. The matter 

is not resolved simply by noting--as the government

does--that Mr. Gantt's testimony could, if believed, have 

had great probative force and might have constituted more 

"compelling evidence" than Sergeant Gubbei's testimony. It 

is certainly possible that Mr. Mathis's jury would have 

convicted on the basis of Mr. Gantt's testimony alone, but 

we would hesitate before terming such a result "highly 

probable." Nor is it enough to find--as Mr. Mathis 

urges--that skeptical jurors might, with reasonable

justification, have disbelieved both Mr. Gantt and Sergeant 

Gubbei. Reasonable doubt is the proper test for harmless 

error analysis concerning constitutional rights, e.g., Neder 

v. United States, 527 U.S. 1, 16 (1999), but a less stringent 

standard regulates non-constitutional errors such as this 

one, e.g., Kotteakos, 328 U.S. at 764-65; Jannotti, 729 F.2d 

at 220 n.2. 

The crux of our analysis derives, not from any piece of 

testimony in isolation, but from the interlocking 

correspondence of evidence throughout the record. For 

example, it is not disputed that the testimony of several 

eyewitnesses, located inside and outside the bank building, 

confirmed Mr. Gantt's basic description of how the Sun 

National Bank robbery occurred. Photographs produced 

from the bank's video security cameras were similarly 

corroborative of this testimony. Also, Mr. Gantt's account of 

the robbers' foiled attempt to escape in the Jeep was 

virtually identical to Sergeant Gubbei's description of the 

same events from the perspective of his police cruiser. Mr. 

Gantt's identification of Mr. Seaberry as one of the coconspirators was confirmed by an arresting officer's 

testimony that Mr. Seaberry was apprehended near the 

stalled Jeep, and the arrest of Mr. Seaberry also tended to 

corroborate Mr. Gantt's account of how he and Mr. Mathis 

(but not Mr. Seaberry) finally escaped. 

Giving Dr. Loftus's testimony its full weight, a jury might 

have had reasonable cause to doubt Sergeant Gubbei's 

description of events, if such description were viewed in 

isolation. But here, where the disputed eyewitness account 

was repeatedly confirmed by a co-conspirator's testimony, 

 34 
and where various aspects of that co-conspirator's 

testimony were in turn confirmed by other available

evidence, we think it highly improbable that a jury that 

voted to convict without the aid of Dr. Loftus's testimony, 

would, had it heard that testimony, have reached a 

different verdict. 

III. Conclusion 

For the foregoing reasons, the District Court's judgment 

of conviction is affirmed. 

A True Copy: 

Teste: 

 Clerk of the United States Court of Appeals 

 for the Third Circuit 

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