## Facts

- Calvin Minor was charged in the Superior Court of the District of Columbia with armed carjacking, armed robbery, possession of a firearm during a crime of violence, and unauthorized use of a vehicle arising from a carjacking outside a convenience store.
- The complainant, Crystal Nunnley, testified a young man pointed a gun at her, took her keys, and drove away in her car.
- Nunnley described being terrified; the encounter lasted only seconds; and she said focusing on the gun helped her remember the assailant’s face.
- The prosecution’s case substantially relied on Nunnley’s eyewitness identification.
- Minor sought to present expert testimony from Dr. Ronald Fisher, a psychology professor, about research on factors affecting eyewitness accuracy (including brief exposure and weapon presence).
- The trial court excluded the expert testimony, and the jury convicted Minor on all counts.
- On a first appeal, the D.C. Court of Appeals remanded for a hearing and reconsideration of admissibility under the Dyas framework as guided by later eyewitness-expert precedents.
- On remand, the trial court found Dr. Fisher qualified but again excluded the testimony under Dyas factor (2), reasoning the conclusions were “equivocal” and the studies did not reflect “real world” conditions.

## Issues

1. Whether the trial court abused its discretion by excluding Dr. Fisher’s expert testimony on eyewitness-identification reliability under Dyas factor (2) on the grounds that the testimony was “equivocal” and the supporting research did not replicate real-world conditions.

## Decision

- The D.C. Court of Appeals held the trial court abused its discretion in excluding Dr. Fisher’s testimony.
- The court concluded the proffered testimony satisfied the Dyas admissibility framework as applied to eyewitness-identification expertise.
- The court ruled that the trial court’s objections (equivocal conclusions and imperfect real-world correspondence) concerned weight for the jury, not threshold admissibility.
- The court reversed and remanded for further proceedings consistent with its opinion.

## Legal Principles

- Expert testimony is admissible under Dyas when: (1) the subject is beyond the ken of the average lay juror; (2) the expert’s knowledge will probably aid the factfinder; and (3) the state of the relevant scientific knowledge permits a reasonable expert opinion.
- Empirically grounded expert testimony on eyewitness-identification reliability may satisfy Dyas because many determinants of eyewitness accuracy (e.g., stress and weapon focus) are not intuitive to lay jurors.
- Under Dyas factor (2), probabilistic or qualified conclusions in social-science testimony generally affect credibility and persuasiveness, not admissibility; cross-examination and contrary evidence are the standard tools for testing such limits.
- The fact that experimental research does not replicate all real-world variables does not, by itself, justify exclusion where the field provides a sufficient empirical basis for reasonable expert opinions.

## Conclusion

The court held that excluding a qualified eyewitness-identification expert because the testimony was qualified and based on studies not perfectly mirroring crime conditions misapplied Dyas by treating weight concerns as admissibility barriers, requiring reversal and remand.


Minor v. United States, 57 A.3d 406 (D.C. 2012)