New Mexico Lawyer Sanctioned for ChatGPT-Fabricated Legal Brief

Aarons, representing client Oscar Sandoval on a murder appeal, fed trial transcripts and case materials into ChatGPT running OpenAI's o3 model, expecting it to produce a 'bulletproof summary' of the proceedings ^[1]. Instead, the tool invented four witnesses who never testified, including two purported police officers, Officer Michelle Amarillo and Officer Sanchez, alongside two civilian names, Manal Al-Jibury and Teresa Marquez ^[1]. The fabricated testimony included granular invented details, such as a description of the shooter wearing dark pants and a white shirt ^[2], and the filing also attributed false statements to real witnesses, blending fact and fabrication in a way that would be nearly impossible to catch without cross-checking the original transcript ^[1].

The case echoes the 2023 Mata v. Avianca episode, in which two attorneys and their firm were fined $5,000 for citing six ChatGPT-invented court cases ^[7], but it marks an escalation from fabricated case law to fabricated trial testimony in a capital murder case. Courts have hardened their responses since then - a Central District of California special master struck briefs and ordered $31,100 in fees after a filing mixed erroneous outputs from three different AI tools ^[5], and a Wyoming federal judge revoked an attorney's pro hac vice admission over eight fabricated citations ^[5]. An industry tracker recorded roughly 200 AI-hallucination sanctions cases in mid-2025, growing to 719 by January 2026, 1,227 by early April 2026, and 1,598 by June 9, 2026 ^[6].

Justice C. Shannon Bacon pressed Aarons at the sanctions hearing, asking, 'Counsel, do you watch the news? Do you listen to the radio? Do you read anything about what's going on in the world?' ^[2]The court held him in direct contempt and fined him $5,000, payable within 30 days to the State Bar of New Mexico Client Protection Fund ^[1]. It struck all of Aarons' earlier briefs, appointed a public defender, and barred him from appearing before the state's highest court pending a Disciplinary Board investigation ^[1], finding that he had shown 'a lack of remorse and a lack of concern for his client' ^[2]. Aarons said he was 'remorseful but hopeful that the disciplinary board takes into account it was an honest mistake' ^[1].

The client, Oscar Renee Sandoval, is serving a life sentence for murdering the mother of his children ^[3]. His appeal must now be re-briefed from scratch by newly appointed public defender Kim Chavez Cook ^[4], adding delay to a capital case through no fault of his own, purely because his own lawyer filed unverified AI output with the court.