New Mexico lawyer fined $5,000 for filing ChatGPT-fabricated evidence in murder appeal

The New Mexico Supreme Court has fined a veteran defense attorney $5,000 and held him in contempt after he submitted an appeal brief in a murder case filled with fake witnesses and invented police testimony generated by ChatGPT.

Stephen Aarons, a Santa Fe lawyer with more than 40 years of experience, admitted he used the AI chatbot to draft the brief for his client, Oscar Renee Sandoval. The document included fabricated quotes from non-existent police officers and fictional statements from witnesses who were never called to testify at trial.

Sandoval was sentenced to life in prison in February 2025 for the murder of his partner, Shiereen Al-Jibury. Aarons, who was hired by Sandoval's family, filed the brief containing the errors in August 2025.

What went wrong with the AI

According to court records, Aarons generated the material by feeding an automated trial transcript and other case files into ChatGPT. He told the court at an August hearing that he used OpenAI's o3 model, assuming it would provide a "bulletproof summary" of the proceedings.

Instead, the AI invented entirely fictional people—including Officer Michelle Amarillo, Officer Sanchez, and a witness named Teresa Marquez—and manufactured details about the shooter's clothing. It also created fake testimony about threats supposedly received by another witness, Danny Stanton.

While Aarons did not cite non-existent cases, he admitted that his brief inaccurately described real legal precedents.

'You buried your head in the sand'

The justices were unimpressed by Aarons' claim that he did not realize artificial intelligence could make things up.

"Counsel, do you watch the news? Do you listen to the radio? Do you read anything about what's going on in the world?" Justice C. Shannon Bacon asked during the hearing, noting that stories about lawyers submitting AI hallucinations are widely publicised. She accused Aarons of either making an intentional choice to remain uninformed or taking a gamble, neither of which complied with professional standards.

Justice Bacon added that there is no material difference between citing a fake case and misrepresenting a real one, as the rules of candor to the court apply equally to both.

The impact on the client

The court also criticised Aarons for failing to tell his client what had happened. Aarons admitted he had only told Sandoval's family that there was "a problem" with the brief, but did not mention ChatGPT.

"Your client is the one suffering because of this far more than you will ever suffer," Justice Bacon said.

Chief Justice Julie Vargas expressed frustration that Aarons wanted to discuss future AI policies rather than the immediate crisis facing his client. She noted that Sandoval remains in custody while his appeal is delayed.

What happens next

Under the Supreme Court's order, Aarons is barred from practicing before the state's highest court while an attorney disciplinary board investigates the matter. The $5,000 fine will be paid to the State Bar of New Mexico Client Protection Fund.

The court has struck the tainted briefs from the record and ordered the public defender's office to assign a new attorney to Sandoval's appeal. Kim Chavez Cook has since taken over the defense, and the case will proceed in the court's 2026-27 term.

In a statement, Aarons said using ChatGPT was an "honest mistake" and that he is remorseful. "I didn't know that AI could hallucinate facts," he said, calling the experience "a lesson learned for all professionals who rely upon this powerful but sometimes unstable technology."