## Facts

- David Crumby, a bank employee, was indicted for bank robbery and aiding and abetting under 18 U.S.C. §§ 2113(a) and 2 based on the government’s theory that he acted as an “inside man” in a Bank One robbery in Chandler, Arizona.
- A confessed robber identified Crumby as the inside participant.
- Crumby had no prior criminal record and maintained his innocence.
- To support his claim of innocence, Crumby voluntarily took a polygraph examination administered by a former police polygrapher.
- The examiner concluded Crumby was truthful in denying involvement and that he passed the examination.
- Before trial, Crumby moved for an evidentiary hearing on the reliability and admissibility of the polygraph results.

## Issues

1. Whether polygraph evidence may be admitted under Federal Rule of Evidence 702, as construed by Daubert, despite prior circuit skepticism toward unstipulated polygraphs.
2. If admissible, under what limited purpose and procedural conditions the defendant’s polygraph evidence may be introduced at trial.

## Decision

- The court granted the motion in part after an evidentiary hearing.
- The court held polygraph evidence is not categorically inadmissible and may qualify as scientific evidence under Rule 702 when reliability is established under Daubert.
- The court limited admissibility to impeachment/support of the defendant’s credibility, not as general substantive proof of innocence.
- The defendant could introduce evidence that he took and passed a polygraph only if:
  - the prosecution attacked his credibility, and
  - the prosecution impeached his testimony by contradiction.
- The court required procedural safeguards, including sufficient notice and a reasonable opportunity for the government to administer a similar polygraph examination with its own expert.
- The court emphasized the ruling was confined to the case’s facts and designed to reduce unfair prejudice and jury confusion.

## Legal Principles

- Scientific or technical evidence is admissible under Federal Rule of Evidence 702 when it is relevant and reliable and will assist the trier of fact.
- Under Daubert, the trial court serves as gatekeeper and evaluates reliability using flexible considerations such as testability, peer review, error rates, standards controlling the technique, and general acceptance.
- Polygraph evidence can satisfy Rule 702 in some circumstances, but its probative value must be weighed against risks of undue prejudice and juror misuse.
- Polygraph results may be admitted in a narrowly limited impeachment posture to rehabilitate a defendant’s credibility after the prosecution attacks credibility and contradicts testimony.
- Fairness may require reciprocal testing opportunities and advance notice when a party seeks to introduce polygraph evidence.

## Conclusion

The court allowed the defendant’s polygraph results only as tightly constrained impeachment evidence under Rule 702 and Daubert, conditioned on credibility-based triggering events and procedural protections, while rejecting any broad rule of general polygraph admissibility.


United States v. Crumby, 895 F. Supp. 1354 (D. Ariz. 1995)