First of all:
Secondly: Last semester I had a terrible roommate (who moved out and now I have a single room. Never having a room that is not to myself again). She tended to get in at 3am in the morning, while I was sleeping, and was loud and obnoxious at times. She even became a representative for a thing that is not dis-appropriate, and adorned our door announcing that she is a rep
Needless to say, she only took it down when her parents were in town
Many times she'd have guests overnight without telling me, and her party friends were as loud and obnoxious as she was and put obnoxious things on our door.
I dealed with the first situation, it wasn't that bad, but I knew she was trying to be quiet.
The second situation I told her that I was against the concept, but that I was not going to be doing her job for her.
I just dealt with the third situation as well, because it was mainly petty more than anything. If it would've happened more times, I would've brought the topic up with her.
I know I wasn't the best roommate either, being slightly messy at times. However, she asked me to clean up a few times, and I did so.
Try talking with her about it again, that seemed to help me and my roommate. She seems to be wanting to be rebellious, so just have a sit-down-talk with yourself, her, and your RA if it needs to be. Or the head RA of the complex even. Drag her to the meeting if you have to. I agree with the PP saying that a campus police officer should attend. The safety issue is what is most important, and should be dealt with immediately.