In a nutshell: Users have long been warned to be careful what they tell ChatGPT, especially if it could get them in trouble with the law. California prosecutors, for example, used the chatbot's logs in their case against the man accused of starting a blaze that became the Pacific Palisades fire of 2025.
Jonathan Rinderknecht was accused of deliberately starting last year's fire, which killed a total of 31 people and destroyed more than 6,000 buildings.
The prosecution's case included everything from his iPhone's location data and security camera footage to witness testimonies.
Prosecutors also used Rinderknecht's ChatGPT logs. They said he used the tool to generate an image depicting a city on fire, asked the AI "why am I so angry all the time?" and went on tirades about how the rich were destroying the world – allegedly influencing his decision to start the blaze in a wealthy neighborhood.
– F.A. United States Attorney Bill Essayli (@USAttyEssayli) June 26, 2026
Rinderknecht is said to have used ChatGPT like a diary. One prompt asked if he could be held responsible for a fire that was caused by his fallen cigarette.
Prosecutors said that Rinderknecht was motivated by revenge, anger, and loneliness because he had nowhere to go for the holiday.
The trial against Rinderknecht ended last week. After two days of deliberation, the jury voted 10-2 in favor of the defense, leading the judge to declare a hung jury and a mistrial.
Defence attorney Steve Haney argued that Rinderknecht – who has both French and US citizenship and is a former Uber driver – had not started the blaze and had called authorities after seeing the fire break out.
While the ChatGPT evidence might appear damning, a juror told CBS LA that she didn't believe the logs proved anything, noting that she talked to the bot all the time. She added that it made her "angry" that Rinderknecht's use of ChatGPT was being framed as a character flaw.
The decision doesn't mean the case against Rinderknecht is over. A retrial has been scheduled for October this year, with Rinderknecht remaining in custody until then.
This isn't the first time that ChatGPT has been caught up in a criminal investigation. Florida Attorney General James Uthmeier announced in April that the Office of Statewide Prosecution launched a criminal investigation into OpenAI and ChatGPT over its role in a school shooting last year.
"If ChatGPT were a person, it would be facing charges for murder," Uthmeier said in a previous news release.