New Mexico Supreme Court punishes lawyer for fake testimony in AI brief

In short: New Mexico’s Supreme Court held a longtime defense lawyer in contempt after he filed an appeal brief that included made-up witness testimony generated with ChatGPT.

What happened

The New Mexico Supreme Court said attorney Stephen Aarons submitted an appeal brief that contained “false testimony from wholly fabricated witnesses.” The court said the brief included invented police testimony and other incorrect claims.

In a court order, the justices said Aarons admitted he did not check the facts or the legal citations in the AI-generated sections before he signed and filed the document. The court also said he did not tell his client about the failure, even after problems were raised.

Aarons told the court he fed an AI-made trial transcript and other case documents into ChatGPT. The output included quotes from witnesses who never testified, plus other errors. This is an example of “hallucinations,” which is when an AI tool confidently makes things up (like a calculator that sometimes invents numbers, while still looking sure).

The court fined Aarons $5,000, to be paid to the State Bar of New Mexico Client Protection Fund. It also barred him from appearing before the state Supreme Court while a disciplinary board investigates. The court threw out the earlier briefs, ordered a new lawyer to be appointed for the defendant, and said the appeal will move forward in the court’s 2026 to 2027 term.

Why it matters

This case is a reminder that AI writing tools can produce believable but false details, and that professionals are still responsible for checking their work. In court, errors can delay cases and harm the person depending on the filing, especially a defendant who is in custody.

Source: Arstechnica