## Facts

- A Univest Bank branch in Warminster, Pennsylvania was robbed at gunpoint on January 18, 2006; the robber carried an umbrella, displayed a handgun, vaulted the teller counter, and took about $6,421.
- The government linked Lacey Graves to the robbery through physical and identification evidence, including an umbrella allegedly discarded in the bank, shoeprint impressions from the teller counter, sneakers seized from a third party’s residence, and DNA testing.
- DNA from the umbrella and both sneakers was compared to a known sample from Graves using PCR/STR analysis; the sneaker swabs were mixtures reflecting DNA from three or more individuals.
- Reported random-match probabilities (African-American population) were approximately 1 in 2 for the umbrella sample, and approximately 1 in 2,900 (left sneaker) and 1 in 3,600 (right sneaker).
- An FBI footwear examiner compared counter impressions to the seized sneakers and reported limited associations (design and approximate size correspondence for one; similar design features for another), not an individualizing match.
- A bank assistant manager made a photo identification of Graves as the robber.
- Before trial, the parties filed motions in limine addressing admissibility of (1) umbrella DNA, (2) sneaker DNA, (3) shoeprint-comparison testimony, and (4) defense expert testimony on eyewitness-identification reliability.

## Issues

1. Whether umbrella DNA evidence with extremely low statistical significance should be excluded under Federal Rule of Evidence 403 due to risk of unfair prejudice and confusion.
2. Whether sneaker DNA mixture evidence with probabilities in the thousands should be admitted under Rule 403 given its probative value and the risk jurors might overvalue DNA evidence.
3. Whether non-definitive shoeprint comparison testimony is admissible under Rules 702 and 403 when it describes limited correspondence rather than a conclusive match.
4. Whether defense expert testimony on eyewitness-identification reliability satisfies Rule 702 and Daubert, including the “fit” requirement, and should be presented to the jury.

## Decision

- The court excluded the umbrella DNA evidence under Rule 403.
- The court admitted the sneaker DNA evidence, rejecting the Rule 403 objection.
- The court admitted the shoeprint comparison testimony, subject to presentation that accurately conveys its limitations.
- The court admitted the defense expert testimony on eyewitness-identification reliability under Rule 702 and Daubert.
- The court did not terminate the prosecution; it resolved these matters as pretrial evidentiary rulings.

## Legal Principles

- Under Rule 403, DNA evidence may be excluded when its probative value is minimal yet the “DNA” label creates a substantial risk of jurors giving it undue weight, causing unfair prejudice or confusion.
- DNA mixture evidence with stronger statistical support may be admissible under Rule 403 when it meaningfully tends to connect the defendant to relevant physical items and the risk of unfair prejudice does not substantially outweigh probative value.
- Pattern-comparison evidence (such as footwear impressions) can be admissible under Rules 702 and 403 even without a definitive match if the methodology is sufficiently reliable and the examiner clearly states the limited strength of the association; weaknesses generally go to weight, tested by cross-examination.
- Expert testimony on eyewitness-identification reliability may satisfy Rule 702 and Daubert when grounded in reliable research and when it assists the jury in assessing identification evidence without instructing the jury how to decide credibility.

## Conclusion

The court drew Rule 403 distinctions based on the strength of forensic statistics and the risk jurors may overvalue scientific evidence, excluding non-discriminating umbrella DNA while admitting more probative sneaker DNA and qualified shoeprint comparisons, and it permitted a defense expert to educate the jury about empirically documented factors affecting eyewitness identification reliability under Rule 702 and Daubert.


United States v. Graves, 465 F. Supp. 2d 450 (E.D. Pa. 2006)