A 20-year-old man allegedly tossed a molotov cocktail at the home of Sam Altman, OpenAI’s CEO, before the sun rose on Friday, according to statements from San Francisco police.

The suspect, who allegedly threw the fire bomb at the $27m North Beach residence around 4.12am, has been arrested but not identified. The same person allegedly threatened to torch OpenAI’s headquarters in the city. No injuries were reported.

The San Francisco police wrote in a statement on X on Friday morning that the agency responded to a “fire investigation” after the man allegedly threw a molotov cocktail at Altman’s residence. Law enforcement said there was a “fire to an exterior gate”, after which the suspect fled on foot. There were no injuries, the agency said.

About an hour later, just after 5am, police responded to reports from a business in the Mission Bay neighborhood, where OpenAI’s headquarters are located, about a man “threatening to burn down the building”. Officers said they recognized the man as the suspect from the earlier incident and immediately detained him.

OpenAI, best known for making the popular ChatGPT chatbot, confirmed the incident in an emailed statement. “Early this morning, someone threw a Molotov cocktail at Sam Altman’s home and also made threats at our San Francisco headquarters. Thankfully, no one was hurt,” a spokesperson said. “We deeply appreciate how quickly SFPD responded and the support from the city in helping keep our employees safe. The individual is in custody, and we’re assisting law enforcement with their investigation.”

OpenAI sent a note informing employees on Friday morning about the incident, and told them there was no immediate threat to them or other offices. The note also mentioned that there would be increased police and security presence around its Mission Bay offices.

Last year, OpenAI locked down its San Francisco office after the company reported a threat from a person once affiliated with an anti-AI activist group.