There are just some messed up people in the world and video games are not the reason for them. If a guy wearing a spiderman suit, thinking webs would shoot from hands, jumped off a building and died, would the movies be to blame? No, because he was stupid enough to try. The problem these days is that a lot of people lack common sense. Besides, this was most likely a sadistic murderer from the beginning, since that kind of behaviour can't just manifest itself from nowhere or can it?