New Mexico Supreme Court punishes lawyer for using ChatGPT to cite fake witness testimony

The state's highest court found that Aarons, a criminal defense lawyer with more than 40 years of experience, admitted he did not verify the factual claims or legal authority in his AI-generated brief before signing and filing it. He also failed to inform his client about the errors. The brief was filed on behalf of Oscar Renee Sandoval, who was sentenced to life in prison in February 2025 after being convicted of murdering his partner and the mother of his children, Shiereen Al-Jibury.

The court's order stated that Aarons "admitted to the Court that he did not verify the factual claims and legal authority in his AI-generated brief before signing it and filing it with the Court, and that he did not inform his client of this failure or that the brief in chief contained multiple factual and legal misrepresentations."

The Supreme Court held Aarons in direct contempt and referred him to a disciplinary board for further proceedings. The case underscores the risks of relying on generative AI tools for legal work without proper human oversight.

Why This Matters

The ruling reinforces that lawyers remain fully responsible for the accuracy of court filings, even when using AI tools. Clients and the justice system can be harmed by fabricated content.
This case goes beyond earlier incidents of AI-generated fake case citations by involving entirely made-up witness testimony, raising the stakes for legal ethics.
The outcome could influence how courts and bar associations address the use of AI in legal practice, potentially leading to stricter guidelines or mandatory disclosure rules.

Background

The incident is part of a growing pattern of lawyers using large language models like ChatGPT to draft legal documents without adequate review. In previous high-profile cases, attorneys have submitted briefs citing nonexistent judicial opinions generated by AI. The New Mexico case marks an escalation, as the AI-created content included fabricated police testimony and other factual claims that were presented as real evidence in an appeal.

Key Perspectives

The New Mexico Supreme Court: Emphasized that submitting unverified AI-generated content undermines the integrity of the judicial process. The court found Aarons showed "a lack of remorse and a lack of concern for his client."
Attorney Stephen Aarons: Admitted to the court that he failed to check the AI-generated brief and did not inform his client about the misrepresentations. He now faces potential disciplinary action, including possible suspension or disbarment.
Legal ethics experts: Likely view this as a cautionary example that the duty of competence and candor cannot be delegated to AI. The case may prompt bar associations to update guidance on the ethical use of generative AI.

What to Watch

The disciplinary board's final recommendation and any sanction imposed on Aarons.
Whether the Sandoval appeal is affected and if the fabricated brief leads to further litigation.
Potential new state bar rules or court orders requiring lawyers to certify AI-generated content.

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