This is the closest I've ever come to hating someone

I'm so angry right now. I can't believe this, it's completely ridiculous - and I should have seen it coming soon. For the past few weeks it has become painfully obvious that my roommate's boyfriend is emotionally manipulating and abusing her. He tells her that she's fat and needs to eat less, but that she shouldn't worry because he still loves her. He whines for her to come over and "keep him company" at like 2:00am when she's tired, it's dark and rainy out. He tells her who she can and can't hang out with, and he was so rude to her mother that she told Jamie that she was shocked and appalled by him. When he was drunk he told her he was thinking about breaking up with her because she wouldn't sleep with him. But here's the kicker: last night he barged into our apartment (there are four of us living here) and one of my other roommates made the comment that he should knock before coming into someone else's home. A few minutes later Jamie storms out of the apartment with her boyfriend, her hands full of her stuff, and slams the door behind her. This afternoon I came back from work to find a good portion or her things gone and her number scratched off our phone list with "don't call again" written in next to it. Nothing we said would have made her this mad - nothing. It makes me so angry because I have no idea what he told her, and she won't take any of our calls because of what he told her. This is so frustrating!!! He has no right to do this to her, to us! He's been trying to get her to move in with him for weeks and she won't do it because she was planning on breaking up with him after Valentine's Day - now she's living with him. We can't find out what he told her - he won't talk to us, and won't let her talk to us. God... I just want to beat his head against the wall until he understands how much he's hurt her and what he's doing is wrong.