## Facts

- Frank Javier Cordoba was stopped while driving a van containing roughly 300 kilograms of cocaine and was charged with possession with intent to distribute.
- Cordoba asserted a lack-of-knowledge defense, claiming he did not know the van contained cocaine.
- To support his credibility, Cordoba sought to introduce results of an unstipulated polygraph examination indicating he was truthful about lacking knowledge.
- The district court originally excluded the polygraph evidence and Cordoba was convicted.
- On a prior appeal, the Ninth Circuit held that unstipulated polygraph evidence could not be treated as categorically inadmissible after *Daubert* and remanded for individualized admissibility findings under Rules 702 and 403.
- On remand, the district court conducted a two-day evidentiary hearing with extensive submissions, found polygraph evidence unreliable under Rule 702 and unduly prejudicial under Rule 403, excluded the evidence, and reinstated the conviction.

## Issues

1. Whether the district court abused its discretion, after a *Daubert*-style evidentiary hearing, by excluding Cordoba’s unstipulated polygraph evidence under Federal Rules of Evidence 702 and 403 and reinstating his conviction.

## Decision

- The Ninth Circuit affirmed the order excluding the polygraph evidence and affirmed the reinstated conviction.
- The court held the district court did not abuse its discretion in finding the proffered polygraph results inadmissible under Rule 702 due to insufficient scientific reliability and standards.
- The court also held the district court did not abuse its discretion in excluding the evidence under Rule 403 because any limited probative value was substantially outweighed by risks of unfair prejudice, confusion, and misleading the jury.

## Legal Principles

- Unstipulated polygraph evidence is not categorically inadmissible; admissibility must be decided case-by-case under Rules 702 and 403.
- Under Rule 702 and *Daubert*, trial courts must act as gatekeepers and may assess testing, peer review, error rates, standards controlling the technique, and acceptance within the relevant scientific community.
- A district court may exclude polygraph evidence where the record supports findings of unresolved scientific controversy, absence of dependable real-world error rates, or inadequate governing standards.
- Reliability analysis may consider both the general validity of polygraph techniques and the specific administration and scoring of the defendant’s examination.
- Under Rule 403, a court may exclude otherwise relevant evidence if its probative value is substantially outweighed by dangers of unfair prejudice, confusing the issues, or misleading the jury, including the risk that jurors will give polygraph results undue weight.

## Conclusion

The Ninth Circuit upheld the exclusion of Cordoba’s unstipulated polygraph results because the district court permissibly found the evidence insufficiently reliable under Rule 702 and, independently, more prejudicial than probative under Rule 403, warranting reinstatement of the conviction.


United States v. Cordoba, 194 F.3d 1053 (9th Cir. 1999)