## Facts

- Lashay Marie Lopez, a convicted felon on probation, purchased a handgun at a sporting goods store using her identical twin sister’s identification.
- Lopez admitted the purchase and the use of false identification; the only disputed trial issue was her affirmative defense of duress.
- Lopez asserted that Hector Karaca, a former boyfriend recently released from prison and sought in connection with serious violence, came to her home and threatened to harm her and her family unless she obtained a gun for him.
- Lopez sought to introduce expert testimony from Dr. Cheryl Karp concerning Battered Woman Syndrome (battering and its effects) and the impact of past abuse on a victim’s perceptions and behavior.
- Lopez proffered the expert testimony to explain her fear response and to help the jury understand why she did not contact police or otherwise avoid the conduct, behavior the defense characterized as counterintuitive without expert context.
- The district court excluded the expert testimony, reasoning that duress is governed by an objective “reasonable person” standard and that battering-effects evidence was therefore irrelevant; it allowed only Lopez’s lay testimony about her abuse history and state of mind.
- A jury convicted Lopez of making a false statement in connection with a firearm purchase, aggravated identity theft, and being a felon in possession of a firearm.

## Issues

1. Whether expert testimony on battering and its effects is relevant and admissible to support a duress defense notwithstanding duress’s objective “reasonable person” standard.
2. Whether excluding the expert testimony prejudiced Lopez’s duress defense, requiring vacatur and a new trial.
3. Whether the district court abused its discretion by excluding a video recording of Lopez’s jail interview with ATF agents.

## Decision

- The Ninth Circuit vacated the convictions and remanded for a new trial.
- The court held the district court committed legal error by excluding expert testimony on battering and its effects offered to support the duress defense and rehabilitate credibility.
- The court held the error was prejudicial because duress was the sole contested issue and the excluded testimony went directly to the reasonableness of Lopez’s fear and perceived alternatives.
- The court affirmed the district court’s exclusion of the ATF interview video because it would have been almost entirely hearsay, including the defendant’s own statements.

## Legal Principles

- A duress defense applies an objective standard, but the “reasonable person” assessment is made in light of the defendant’s circumstances.
- Expert testimony on battering and its effects may be admissible to help a jury evaluate whether fear of serious harm was reasonable and whether a reasonable, lawful alternative existed.
- Such expert testimony may also be used to address common juror misconceptions and to explain seemingly counterintuitive conduct (e.g., not seeking police assistance), bearing on the defendant’s credibility and the duress elements.
- Excluding central defense evidence is prejudicial when it substantially impairs the defendant’s ability to present the only contested defense at trial.

## Conclusion

The Ninth Circuit held that battering-and-its-effects expert testimony can be relevant to an objective duress inquiry by informing the jury’s evaluation of a reasonable person in the defendant’s circumstances; because excluding that testimony materially undermined Lopez’s only defense, the court vacated and ordered a new trial while upholding a separate hearsay-based exclusion of an interview video.


United States v. Lopez, 913 F.3d 807 (9th Cir. 2019)