Sf Chronicle speaks of an "alleged attack", where a Molotov Cocktail was thrown at the outer gate. Looking at the picture there was zero chance of the house catching fire.

https://www.sfchronicle.com/crime/article/molotov-cocktail-c...

So the arrested suspect is either the wrong person, did not actually want to kill anyone or has no clue how fire spreads.

A strange incident that will make many people think of sending a noose to oneself (where oneself does not have to be Altman, but a pro-AI org who wants to generate sympathy).