Unreported / Non-Citable
Background
In April 2025, surveillance video captured Crystal Gillespie and two others spending about 50 minutes taking merchandise from a Marshalls store and loading it into a U-Haul truck. The driver led police on a 15-minute, nine-mile high-speed chase, and Gillespie was found hiding in the cargo area. Police recovered $1,673 in merchandise and a glass pipe with burnt residue. Charged with grand theft while acting in concert and with a prior strike, she was held to answer.
In January 2026, Gillespie moved for pretrial mental health diversion under Penal Code section 1001.36, submitting a report from forensic psychologist Dr. Lauren Vickerman diagnosing severe bipolar I disorder, generalized anxiety disorder, and severe methamphetamine use disorder, and opining that those conditions directly contributed to the alleged theft. The People conceded the qualifying diagnoses, which triggered a statutory presumption that the disorders were a significant factor in the offense unless rebutted by clear and convincing evidence, and relied on their own expert, Dr. Nicole Friedman, who disclosed using AI to help generate her report.
Friedman reviewed the arrest report, charging documents, both Vickerman reports, and two short surveillance videos, opining that the conduct was organized, goal-directed, and collaborative, reflecting intact executive functioning. At the March 2026 hearing before Judge Melinda Lasater, the trial court admitted Friedman's report over Gillespie's AI-based objection, found her ineligible for diversion without reaching suitability, and denied reconsideration. Gillespie petitioned for a writ of mandate in May 2026, and the Court of Appeal issued an order to show cause.
The Court’s Holding
The Court of Appeal agreed in principle that a forensic psychologist's use of AI to generate an expert opinion would presently be a novel scientific technique requiring a Kelly/Frye foundation of general acceptance in the relevant scientific community. But Friedman repeatedly testified that she used ChatGPT only as an organizational tool and not to generate her conclusions. The trial court credited that testimony, and the appellate court deferred to the credibility finding, concluding there was no abuse of discretion in admitting the opinion. Gillespie's separate privacy objection was not renewed in the writ petition, so the court did not address it.
The appellate court acknowledged that some evidence was troubling — Friedman's use of ChatGPT as a 'thought partner' on legal questions, her inability to produce her inputs because she deleted them, and a glaring error in her report stating the medical records showed no acute psychiatric hospitalization — but held that it was not the reviewing court's role to reweigh the evidence or reassess witness credibility.
On the merits, the court held that the trial court applied the correct legal standard under section 1001.36, subdivision (b)(2), rather than an improper 'but for' test, and that substantial evidence supported the finding that the People rebutted the statutory presumption by clear and convincing evidence. Friedman's opinion was not based solely on the absence of information in the police report; she personally reviewed surveillance video showing coordinated, goal-directed, strategic behavior inconsistent with impairment from methamphetamine intoxication or an acute manic or psychotic episode. Although the bipolar and anxiety portion was close, a reasonable factfinder could find clear and convincing evidence of no significant nexus. The petition for writ of mandate was therefore denied.
Key Takeaways
- The Court of Appeal agreed in principle that using AI to generate a forensic expert opinion would be a novel scientific technique requiring a Kelly/Frye reliability foundation, but did not apply that rule because the trial court credited testimony that the expert used ChatGPT only as an organizational tool.
- The court deferred to the trial court's credibility finding on the expert's limited AI use, despite troubling evidence involving her 'thought partner' use, deleted inputs, and a significant factual error in her report.
- The court separately held that the trial court applied the correct legal standard under Penal Code section 1001.36, subdivision (b)(2), rather than an improper 'but for' test.
- Substantial evidence supported the clear-and-convincing finding that Gillespie's mental disorders were not a significant factor in the charged grand theft, based on the expert's personal review of surveillance video showing organized, goal-directed conduct rather than on a mere absence of evidence.
- Because the trial court found Gillespie ineligible, it did not reach the separate suitability criteria under section 1001.36, subdivision (c).
Why It Matters
The decision addresses the emerging use of AI by expert witnesses in criminal proceedings. Although the court did not exclude Friedman's opinion, it stated in principle that AI-generated expert opinions would be treated as novel scientific techniques subject to Kelly/Frye scrutiny; because the trial court credited Friedman's testimony that she did not use AI to generate her opinion, the reliability of AI-assisted analysis was left to the trial court's credibility determinations on appellate review.
The opinion also clarifies the burden for rebutting the statutory presumption of a nexus between a qualifying mental disorder and a charged offense under Penal Code section 1001.36, subdivision (b)(2): an expert's personal observation of offense video can supply substantial evidence of no nexus, while reliance solely on the absence of evidence would not satisfy the clear-and-convincing standard.