## Facts

- Two employees were working at an ice cream shop in Brentwood, Tennessee when a man entered, ordered, displayed a gun, demanded money, and forced both employees into a walk-in freezer.
- Police found no physical evidence at the scene.
- The employees separately described the robber as an obese Black man, about 5′9″ and about twenty years old, and helped prepare composite sketches.
- Nine days after the robbery, one employee identified Eddie L. Coley, Jr. from a photographic lineup; the other employee identified Coley from the same lineup about five months later.
- Identification was the central contested issue at trial; the prosecution relied heavily on the employees’ pretrial and in-court identifications.
- Coley presented an alibi defense and sought to introduce expert testimony (from a proposed expert in eyewitness identification) addressing factors affecting eyewitness reliability.
- The trial court excluded the expert testimony as not helpful to the jury under Tennessee Rule of Evidence 702.

## Issues

1. Whether the trial court abused its discretion under Tenn. R. Evid. 702 by excluding defense expert testimony on the reliability of eyewitness identification.
2. Whether Tennessee law applies a categorical rule admitting or excluding eyewitness-identification expert testimony, or requires case-specific admissibility determinations.

## Decision

- The Tennessee Supreme Court affirmed the conviction.
- The Court held the proffered eyewitness-identification expert testimony was inadmissible under Tenn. R. Evid. 702.
- The Court held the trial court did not abuse its discretion in excluding the testimony.
- The Court rejected both per se admissibility and per se exclusion, requiring a case-by-case evaluation under Rule 702 and the reliability framework used for expert proof.

## Legal Principles

- Expert testimony is admissible under Tenn. R. Evid. 702 only if it will substantially assist the trier of fact and the witness is properly qualified.
- Trial courts have broad discretion over the admission of expert testimony; appellate review is for abuse of discretion.
- Reliability considerations for expert proof may be assessed using factors such as testing, peer review, known or potential error rate, standards controlling the technique, and general acceptance in the relevant scientific community.
- Eyewitness-identification expert testimony is neither automatically required nor automatically barred; admissibility depends on whether the particular proffered testimony is sufficiently reliable and sufficiently helpful to the jury in the specific case.
- A trial court may exclude eyewitness-identification expert testimony where it is not tied to the facts of the case or where the court reasonably concludes jurors can evaluate the identification evidence through ordinary factfinding tools, including cross-examination and credibility assessment.

## Conclusion

The court upheld Coley’s conviction, concluding that the trial judge acted within Rule 702 discretion in excluding the proposed eyewitness-identification expert because it would not substantially assist the jury, while clarifying that Tennessee evaluates such expert testimony case by case rather than by categorical admission or exclusion.


State v. Coley, 32 S.W.3d 831 (Tenn. 2000)