[Dick shrugs a little.] I don't know, I'm not a psychic, or a telepath.

And he's basically a murderous, angry guy who's been here longer than any other inmate without making much progress, from what I can tell, so I don't know if he needs a reason. He's just a jackass who likes hurting people. [If there's anything more to it than that, Dick doesn't know and he doesn't really care.]