US lawyer sanctioned for submitting ChatGPT-fabricated witnesses in murder appeal

Stephen Aarons, a defense lawyer in Santa Fe, made a decision that would cost him $5,000 and his professional standing. He fed trial transcripts and case materials into ChatGPT, expecting the artificial intelligence system to produce what he called a "bulletproof summary" for his client's murder appeal. What he got instead was a brief containing entirely fabricated police testimony and witnesses who never existed—details so specific they included descriptions of a shooter wearing dark pants and a white shirt, statements that appeared nowhere in the actual record.

The New Mexico Supreme Court discovered the fabrication when reviewing Aarons's filing in the appeal of Oscar Renee Sandoval, who had been convicted and sentenced to life in prison for murder. On Wednesday, the court fined Aarons and held him in contempt for failing to verify the accuracy of what he had submitted. The justices went further, noting that Aarons had "demonstrated a lack of remorse and a lack of concern for his client"—a particularly sharp rebuke given that Sandoval's only hope for relief now rested on an appeal that had been compromised by its own defense counsel.

When the court ordered Aarons to explain himself at an August hearing, he acknowledged that he had not fully grasped how AI systems can invent facts wholesale, a phenomenon researchers call "hallucination." Justice C. Shannon Bacon responded with visible exasperation, asking whether Aarons watched the news or read anything about the world, noting that AI hallucinations in legal filings had become "an above-the-fold story every single day." Aarons later told Reuters he was remorseful but characterized the error as an honest mistake born of not understanding the technology's limitations.

The case is not isolated. Courts across the country have begun disciplining lawyers for submitting AI-generated documents without proper review. Dozens have been sanctioned for briefs containing fabricated case citations or misquoted law. But Aarons's filing appears to represent a new threshold—the introduction of wholly invented witness testimony in a criminal appeal, where the stakes involve a person's freedom and the integrity of the judicial process itself.

The New Mexico Supreme Court has referred Aarons to the state's attorney disciplinary board for investigation. His client's appeal has been reassigned to Kim Chavez Cook, a public defender, who declined to comment. The appeal remains pending. Sandoval, who pleaded not guilty to murdering the mother of his children, is serving a life sentence based on a conviction that now must be defended by someone other than the lawyer who initially took up his cause. OpenAI did not respond to requests for comment on how its system came to generate such specific false details, or what safeguards, if any, exist to prevent similar incidents.