## Facts

- Thomas Nimely, age 19, attended a late-night party on Staten Island on February 13, 1998, carrying a loaded handgun that he hid outside the venue.
- After a shooting near the party, NYPD officers pursued Nimely on foot.
- Officer John Muirhead shot Nimely during the chase, leaving Nimely paralyzed from the waist down.
- Accounts conflicted as to whether Nimely turned and pointed a gun at officers immediately before the shot.
- Forensic evidence indicated Nimely was shot in the back.
- At trial, the defense presented expert testimony from Dr. Dawson (forensic pathology/ballistics), who advanced a “misperception” theory to reconcile a back wound with officers’ claims that Nimely faced them.
- Dawson also effectively vouched for the officers by rejecting the possibility that they were lying.
- The jury found for Muirhead; Nimely sought judgment as a matter of law or a new trial based on insufficient evidence and prejudicial evidentiary error.

## Issues

1. Whether, on the properly admitted evidence, a reasonable jury could find for Officer Muirhead on the excessive-force claim, making judgment as a matter of law inappropriate.
2. Whether admitting expert testimony that (a) assessed officer credibility and (b) lacked a reliable methodological foundation was prejudicial error requiring a new trial under the Federal Rules of Evidence.

## Decision

- The court declined to enter judgment as a matter of law for Nimely, concluding a reasonable jury could find for Muirhead on the properly admitted record.
- The court vacated the judgment for Muirhead and remanded for a new trial.
- The court held that the district court committed prejudicial evidentiary errors by admitting expert testimony that intruded on the jury’s credibility function and risked misleading the jury.

## Legal Principles

- Expert testimony is inadmissible to the extent it tells the jury which witnesses are truthful or untruthful; credibility determinations are reserved to the jury.
- Under Federal Rule of Evidence 702, an expert opinion must rest on reliable methods and a reliable application of those methods to the facts, not on speculation or subjective acceptance of a party’s narrative.
- Under Federal Rule of Evidence 403, even relevant expert testimony may be excluded when its probative value is substantially outweighed by the risk of unfair prejudice, confusion, or misleading the jury, including when it carries an undue “aura” of scientific authority in a credibility-driven case.
- When a case turns largely on competing witness accounts, improper expert bolstering of one side’s credibility is likely prejudicial and may require a new trial.

## Conclusion

The Second Circuit held that, although the verdict for the officer could be supported on a properly admitted record, the admission of speculative expert testimony that effectively vouched for police credibility and lacked reliable grounding unfairly affected the trial; the judgment was vacated and the case remanded for a new trial.


Nimely v. City of New York, 414 F.3d 381 (2d Cir. 2005)