My guess, the person would be paranoid but without the drugs he was managing it, controlling it. I would not be surprised if the same applied to this dude, the guy had the violent tendencies, for what ever reason - religion, culture or maybe genetics, and the drugs gave him the will to act it out.

He was most likely a violent and hateful guy but fear of consequences was keeping him in check. The question now is if someone is a person with repressed anger and takes drugs willingly does that excuse him from the consequences of his actions? Would the same apply to drunken wife-beaters?