I'll give you my advice, and listen me on this.
Go to the girl, and say, in a direct way, that you know what's going on, and tell her that you don't want to see her like that. Do this, and you won't feel guilty for not helping her.
Now, she could hear you, and that's great. Now let her break up and then get the girl.
But, let's face it. Probably, she is to much loyal to the bastard. 'What can I do?', you wonder. Forget her. It's the best thing you can do. If you don't, you'll find yourself dragged by her problems.
Take my word on this. Over the last days, I've been in the same exact situation. And I truly cared a lot about the girl. All over the week, people kept telling me what happened, and how bad she was beaten. In a few days, I was dragged by her problems. I was beggining to get affected by her situation, and always having to get in contact with her, dodging her boyfriend, was putting me under extreme stress. I couldn't focus on myself anymore, always thinking how could I help and what I should do.
Luckly, I knew to where I was heading, so I grabbed the fvcking phone and called her. After a few tries (her bf don't let her answer calls from almost anyone) I managed to get an answer. I was direct, and confronted her with the problem. She denied it all. Yet, I knew she was lying. I talked with her, and showed that I cared. She don't want anybody's help.
I tried to help her, and knowing that, I don't feel guilty for not doing something. I finally could calm down, knowing I had done everything I should do, at the very least as a close friend I once was.
Remember that it's not worth it. She has a lot of emotional bagage, and you will only get problems that are not even directly related to you. Just confront it with the situation. If she don't hear you, forget she even exists. Save yourself.
