I think he was specter:he was watching TV(then he did the message)then he locked the doors,drove the car against the tree(he's not dead because he's a ghost)he call Tangerine there and trew the bomb after he went into his room through the walls
I think that is specter he can go trough the walls and so he knows the secrets doors,he also can use acid and that explain the poisonus gas in the cooker