## Facts

- The government prosecuted John W. Downing (“Reverend Claymore”) for participating in a mail- and wire-fraud scheme linked to the Universal League of Clergy.
- The scheme allegedly involved ordering goods on credit at trade shows using fabricated credit references and mail drops to provide false favorable responses to vendors’ credit inquiries.
- The prosecution’s evidence connecting Downing to the scheme consisted solely of eyewitness identifications by twelve witnesses who said they observed “Reverend Claymore” during business dealings for roughly 5–45 minutes.
- The defense sought to present a psychologist as an expert to explain empirically supported factors that can reduce the accuracy of eyewitness identifications and to relate those factors to the identifications in this case.
- The district court excluded the expert testimony on the categorical ground that such testimony could never satisfy Federal Rule of Evidence 702’s “helpfulness” requirement, and Downing was convicted on most counts.
- Downing appealed the exclusion of the expert testimony.

## Issues

1. Whether Federal Rule of Evidence 702 permits a criminal defendant to introduce expert testimony from a psychologist regarding the reliability of eyewitness identifications.
2. What standards govern admissibility under Rule 702’s “helpfulness” requirement, including a reliability assessment and a case-specific “fit” inquiry.
3. How Rule 403’s risk-based balancing (confusion, misleading the jury, waste of time) interacts with Rule 702 for this type of expert evidence.

## Decision

- The Third Circuit vacated the conviction and remanded.
- The court held the district court erred by treating expert testimony on eyewitness identification as categorically incapable of meeting Rule 702’s helpfulness standard.
- The court required a preliminary foundation (in limine) hearing to assess (1) the reliability of the scientific principles and (2) the risk the testimony would overwhelm or mislead the jury.
- The court also required a specific proffer demonstrating “fit,” meaning the expert’s research-based points must connect to particular features of the identifications in the case that could impair accuracy.
- The court instructed that if the testimony is found admissible on remand, the district court must order a new trial; if inadmissible, a new trial is unnecessary.

## Legal Principles

- Expert testimony on eyewitness identification is not per se inadmissible under Fed. R. Evid. 702; admissibility must be determined case by case.
- Rule 702 “helpfulness” requires a preliminary balancing of (1) the reliability and probative value of the expert’s scientific principles and methods and (2) the danger the testimony will confuse, mislead, or overwhelm the jury.
- Rule 702 includes a “fit” requirement: the proponent must show the scientific research addresses specific features of the eyewitness identifications at issue, not merely offer generalized criticism of eyewitness testimony.
- Even if Rule 702 is satisfied, the court retains authority under Fed. R. Evid. 403 to exclude evidence whose probative value is substantially outweighed by risks such as confusion, misleading the jury, undue delay, or waste of time.
- Appellate review of Rule 702 rulings is for abuse of discretion, exercised in light of Rule 702’s generally liberal approach to relevant expert evidence.

## Conclusion

The Third Circuit rejected a categorical bar on psychological expert testimony about eyewitness identification and required trial courts to conduct a foundation hearing assessing reliability, case-specific fit, and potential jury-confusion risks, with Rule 403 serving as an additional screen; because the case rested entirely on identifications, the exclusion was not harmless, so the conviction was vacated and the matter remanded.


United States v. Downing, 753 F.2d 1224 (3d Cir. 1985)