A former Goldman Sachs analyst in Florida has been arrested after allegedly using ChatGPT to discuss plans to sexually assault and kill his ex-girlfriend.

Darren Zhou, 25, was arrested in May after OpenAI alerted the FBI about his conversations with ChatGPT. Investigators later reviewed nearly two months of chat history and said the discussions showed increasingly detailed plans for violence.

According to court documents, Zhou began discussing his ex-girlfriend after their six-month relationship ended in March. He reportedly expressed jealousy over other men in her life and allegedly planned to confront her at a gym parking lot with flowers. If she rejected him, he allegedly discussed shooting her and then killing himself.

Investigators said his alleged plans later expanded to sexual assault, kidnapping and threats against members of the woman’s family. The woman, 21, told police she ended the relationship because of Zhou’s jealous and controlling behavior and feared him enough to break up over the phone.

After the breakup, Zhou allegedly continued contacting her through calls, messages and social media. Even after she blocked his phone number and Instagram account, investigators said he used newly generated numbers through different apps to contact her. Some messages allegedly contained harassment, sexual remarks and threats.

Six days before his arrest, the FBI reportedly alerted the Palm Beach County Sheriff’s Office about Zhou’s conversations. A sheriff’s deputy who reviewed the chats said they appeared to show a progression from anger and frustration to threats and plans for violence.

Zhou was arrested in May and spent two days in the Palm Beach County Jail before being released on $100,000 bail. He faces charges including aggravated stalking, written threats to kill and unlawful use of a mobile phone.