Like RedHedd said, document. My dad is a landlord, and if the police are called to any of his houses more than a certain number of times, they HAVE to leave. Obivously, if they are caught with anything illegal, such as drugs, they have to be out within 24 hours, even if they ARE in jail. When things get bad, call the police, the police should be notifying your landlord when they have to come to the appartment, they are required to...or at least around here.

Good luck, I hope she gets evictedor turns around her behaivior, and I hope everything works out!