The Pulse
New Mexico Supreme Court Fines Lawyer $5,000 Over ChatGPT Brief
The New Mexico Supreme Court held Santa Fe lawyer Stephen Aarons in direct contempt after his murder-appeal brief included fabricated witnesses, false testimony and distorted legal authorities generated with ChatGPT. The court struck the fi
AI.info Team ·
When the New Mexico Supreme Court questioned Stephen D. Aarons about an appellate brief in a murder case, the Santa Fe defense lawyer acknowledged that he had used ChatGPT to prepare it. He also acknowledged that he had signed and filed the document without checking whether its factual claims or legal authorities were accurate.
The court’s answer came in a four-page dispositional order dated September 9, 2026: Aarons is in direct contempt, must pay $5,000 to the State Bar of New Mexico Client Protection Fund and cannot appear before the court while the state Disciplinary Board considers his conduct. The justices also struck every brief filed in the appeal and appointed the Law Office of the Public Defender to take over Oscar Renee Sandoval’s representation.
The order is unusually severe because the filing did not merely contain invented case citations. It included false accounts attributed to police officers and witnesses in a criminal appeal involving a defendant serving a life sentence.
Four Witnesses Appeared in a Brief but Not the Record
Sandoval’s appeal is docketed as S-1-SC-40845. The New Mexico Supreme Court’s order says Aarons admitted that his brief included testimony from four wholly fabricated witnesses: Officer Michelle Amarillo, Officer Sanchez, Manal Al-Jibury and Teresa Marquez.
The document also attributed false testimony to real people. According to the order, the brief claimed that Danny Stanton had received threats from Sandoval and treated them seriously. It added false testimony from Linda Stanton about threats received by her husband, and inserted inaccurate accounts from Mariah Chavez and the fabricated witness Teresa Marquez about the shooter’s clothing and appearance.
The court identified another category of error in the brief: Aarons misrepresented the legal authority in two real New Mexico cases, State v. Lopez and State v. Manus. The justices did not describe the filing as a draft or research memo. It was the brief in chief submitted to the state’s highest court in a live criminal appeal.
The order records that Aarons admitted using ChatGPT “in the preparation of the brief in chief.” It does not say that OpenAI or ChatGPT independently created or filed the document. Responsibility for the filing remained with the lawyer who signed it and submitted it to the court.
Aarons Said He Wanted a “Bulletproof Summary”
Aarons told the court during an August 21 show-cause hearing that he had supplied ChatGPT with a computer-generated transcript and other case materials. He said he expected the system to produce what he called a “bulletproof summary.”
In a statement quoted by Reuters and published by The Guardian, Aarons said he had not understood how extensively AI systems could invent facts. “I am remorseful but hopeful that the disciplinary board takes into account it was an honest mistake,” he said. “It is a lesson learned for all professionals who rely upon this powerful but sometimes unstable technology.”
The court did not accept that explanation as sufficient. Its order says Aarons demonstrated “a lack of remorse and a lack of concern for his client.” The justices also found that he had not told Sandoval that he failed to verify the brief or that it contained multiple factual and legal misrepresentations.
Aarons also failed to tell Sandoval about the show-cause proceedings or give him copies of the filings connected to them, according to the order. Those omissions turned an unreliable document into a client-notification and professional-conduct matter as well as a filing problem.
The Appeal Must Start Again
The court’s sanctions affect the appeal directly. All briefing filed in the case has been stricken. The Law Office of the Public Defender must appoint a new lawyer, who will enter an appearance for Sandoval and receive a new briefing schedule.
The court says the appeal is intended to be heard during its 2026–2027 term. The order does not decide whether Sandoval’s conviction should stand, and it does not resolve any of the underlying claims about the trial. It resets the appellate process after the court rejected the brief as unreliable.
Sandoval pleaded not guilty to killing the mother of his children and was convicted last year, according to Reuters’ account of the case. The appeal remained pending when the court reassigned representation. Kim Chavez Cook, a New Mexico public defender, was assigned to the appeal on September 2, according to that report.
The court’s order also refers Aarons to the Disciplinary Board for further consideration. The referral is separate from the $5,000 contempt sanction. After the board’s investigation and any resulting proceedings, the Supreme Court says it will make further decisions under New Mexico’s attorney-discipline rules.
Justice Shannon Bacon Pointed to a Familiar Warning
The justices’ questions during the August hearing show that the court viewed the case as a basic verification failure, not as an obscure technical problem. Justice C. Shannon Bacon asked Aarons whether he followed public discussion about AI systems and their tendency to produce false information.
“Counsel, do you watch the news? Do you listen to the radio? Do you read anything about what’s going on in the world? Because the problem with lawyers relying on AI hallucinations is an ‘above-the-fold’ story every single day.”
Justice C. Shannon Bacon, at the August 21 hearing, as reported by Reuters
The remark reflects a distinction courts have drawn in several recent cases. Lawyers may use software to organize information, draft language or assist with research, but the lawyer still has to check every factual assertion, quotation and citation before filing. A court filing is not treated as a machine-generated product whose errors belong to the software vendor.
New Mexico’s order states that failure to meet the state’s briefing requirements can support sanctions, including contempt. It also invokes the Supreme Court’s authority to regulate proceedings and discipline attorneys under its constitutional supervisory power over lower courts.
The Case Moves Beyond Fake Citations
Earlier sanctions involving AI-assisted legal work often centered on nonexistent cases or invented quotations. The 2023 federal case Mata v. Avianca, for example, became a widely cited warning after lawyers submitted fabricated authorities generated with ChatGPT. Those cases involved false descriptions of the law.
Aarons’ filing carried the problem into the factual record of a murder appeal. The brief supplied names, statements and descriptions that were not supported by the proceedings. A fabricated citation can undermine an argument; fabricated testimony can alter the account of what happened at trial.
That difference explains why the New Mexico Supreme Court’s order places the lawyer’s conduct alongside his failure to inform his client. The court did not say that using ChatGPT alone violated its rules. It sanctioned Aarons for filing unverified material, misrepresenting facts and law, and failing to disclose the problem to the person whose liberty was at stake.
The order is also careful about what it establishes. It says Aarons admitted using ChatGPT and admitted that the brief contained false testimony and legal misrepresentations. It does not make a finding that OpenAI intended to create false evidence, nor does it assign responsibility for the filing to ChatGPT rather than the attorney.
What the Order Requires From the Next Lawyer
The immediate remedy is procedural: new counsel, new briefing and a hearing during the court’s next term. The disciplinary consequences may take longer. Aarons is barred from appearing before the New Mexico Supreme Court until the board’s investigation and any proceedings are complete, and the court has reserved the right to take further action.
The financial penalty is due within 30 days of the order. Aarons must pay the $5,000 to the State Bar of New Mexico Client Protection Fund and notify the court in writing once the payment is made.
For Sandoval, the concrete result is that his appeal will proceed with a different lawyer and without the brief that was supposed to present his claims. For Aarons, the case now has two tracks: a contempt sanction imposed by the Supreme Court and a disciplinary review that could produce additional action.
The court’s record leaves the operating rule plain. AI can assist with legal work, but a lawyer who files the result owns the verification duty. In this case, the New Mexico Supreme Court struck the brief, reassigned the appeal and ordered Aarons to pay $5,000.