ChatGPT-using lawyer punished for citing fake testimony from made-up witnesses

The New Mexico Supreme Court on Wednesday found veteran defense attorney Stephen Aarons in direct contempt after a brief he filed as part of an appeal contained false testimony from witnesses who were never called at trial and misstatements of legal precedent. The court’s order says Aarons admitted he did not verify the factual assertions and legal citations generated by an AI tool before signing and filing the document. Aarons told the court he used ChatGPT to summarize a trial transcript and related materials and acknowledged that the AI output included quotes and witnesses that did not appear at trial. The order lists several fabricated witnesses by name and says Aarons also misstated testimony from actual witnesses and inaccurately described prior cases. He said he used a version of ChatGPT powered by OpenAI’s o3 model. Justices sharply criticized Aarons’ conduct, saying attorneys must confirm the accuracy of material regardless of its source and that signing a brief requires attesting to its truthfulness. Justice C. Shannon Bacon rebuked Aarons for claiming unfamiliarity with AI “hallucinations,” suggesting that choosing to remain uninformed or gambling on AI accuracy violated multiple provisions of the professional code of conduct. As immediate consequences, the court barred Aarons from appearing before the New Mexico Supreme Court while disciplinary proceedings are pending, imposed a $5,000 fine payable to the State Bar’s Client Protection Fund, struck previous briefs from the record, and directed the public defender’s office to appoint new counsel for the defendant. The court also said the case will be scheduled for its 2026–27 term.