I saw a rape and I don't know what to do

I'm 17 and my friends and I saw a rape last night at a friends party. We were intoxicated and when we left around 3am, we saw a couple fucking in the bushes. He was on top and she was face down. A lot of other people saw it too, and one person even got it on video. But everyone thought they were both just drunk and being stupid. Today though, I found out she was unconscious. The weird thing though, is that she's defending him. My boyfriend and his friends who were at the party too went to the guys house to beat the shit out of him and she was there defending him. She said it's fine and my boyfriend and his friends should go home.