Archive · 11 Sep 2026
New Mexico Court Fines Lawyer Over ChatGPT’s Fabricated Testimony
A lawyer used ChatGPT to help prepare an appeal in a murder case.
The AI produced information about witnesses and testimony that did not exist.
The lawyer included some of that information in a court filing.
New Mexico’s highest court said the filing contained false testimony from fabricated witnesses.
The court fined the lawyer $5,000 and held him in contempt.
It also sent his conduct to a lawyer disciplinary board for investigation.
The lawyer said he made an honest mistake and did not understand how often AI can invent facts.
The defendant’s appeal is still continuing with a new public defender.
The case shows why lawyers must carefully check information produced by AI.
The New Mexico Supreme Court fined defence lawyer Stephen Aarons $5,000 and held him in contempt.
Aarons submitted an appeal brief containing fabricated witnesses and false police testimony generated by ChatGPT.
The court said the filing included fictional claims about the shooter’s clothing.
Aarons said he used ChatGPT to summarize trial materials and did not understand how extensively it could invent facts.
The court will refer Aarons to an attorney disciplinary board while Oscar Renee Sandoval’s murder appeal remains pending.
- Who
- Defence lawyer Stephen Aarons, the New Mexico Supreme Court, and defendant Oscar Renee Sandoval.
- What
- Aarons was fined and held in contempt after submitting an appeal brief containing AI-generated fabricated witnesses and false testimony.
- When
- The court issued the sanction on Wednesday; the appeal was assigned to a new lawyer on September 2, and an August 21 hearing addressed the filing.
- Where
- New Mexico, including the state Supreme Court and the Dona Ana County murder case.
- Why
- The court said Aarons failed to verify material generated by ChatGPT before submitting it in the appeal.
Court’s Findings
Aarons’s Explanation
Responsibility for false material
Court’s Findings
The court said Aarons failed to verify the filing, described the witnesses as wholly fabricated, and said he showed a lack of remorse and concern for his client.
Aarons’s Explanation
Aarons said he used ChatGPT to summarize trial proceedings and other case materials, believing it would produce a reliable summary.
Understanding AI risks
Court’s Findings
The justices expressed disbelief that Aarons was unaware of AI’s ability to generate false information, describing the problem as widely reported.
Aarons’s Explanation
Aarons said he did not understand the degree to which ChatGPT could hallucinate facts and called the incident an honest mistake and a lesson for professionals.
- Lawyer sanctioned
- Stephen Aarons
- Fine
- $5,000
- Court
- New Mexico Supreme Court
- AI tool
- OpenAI’s ChatGPT
- Fabricated material
- False testimony and wholly fabricated witnesses
- Defendant
- Oscar Renee Sandoval
- Appeal status
- The appeal remains pending and was assigned to Kim Chavez Cook on September 2.
