According to San Francisco Police, Moreno-Gama threw a Molotov cocktail at Altman’s house early Friday morning, setting the front gate on fire. No one was hurt.
Police say he then went to OpenAI headquarters, where he was captured on surveillance video throwing a chair at the glass doors. Security told police he said he planned to burn the building down and kill anyone inside.
Moreno-Gama was arrested outside the building by San Francisco police and has remained in custody. Investigators say he was carrying a jug of kerosene and a lighter.
Sources tell Fox News the Justice Department is expected to file federal charges Monday afternoon for attempted damage and destruction of property by means of explosives and possession of an unregistered firearm.
Moreno-Gama is already charged with multiple state felonies, including attempted murder, in connection to the incident at Altman's home.
Altman responded to the attack on his blog with a picture of his family saying, "I love them more than anything," and, "normally we try to be pretty private, but in this case I am sharing a photo in the hopes that it might dissuade the next person from throwing a Molotov cocktail at our house, no matter what they think about me."
Over the weekend, two more people were arrested in a separate incident, after reports of gunfire near Altman’s home, according to San Francisco Police.
"The SFPD takes crimes involving guns extremely seriously, and anyone committing acts like these will be arrested and prosecuted to the fullest extent of the law," said Chief Derrick Lew. "I want to thank our officers whose swift actions identified these suspects, took them into custody, and got dangerous weapons off our streets."
An OpenAI spokesperson told Fox News Digital Monday morning that the incident was unrelated and had no connection to Altman, adding that there was no indication that Altman's home was being targeted.
Fox News' Jesse Watson contributed to this report.