Regardless, Van der Goot says that he was told by the police that he was ultimately responsible for said threat, because the bot was posting under his name and using some combinations of his words. That seems like one of those claims that might be tough to actually arrest someone for--at least under my limited knowledge of U.S. law. It also seems like an unfortunate potential defense for people posting actual death threats online: "Oh, it wasn't me; it was a robot."