Hi hopefully you took pictures prior to moving in, like when you rent a car, do you have the original contract when you first rented the apt? Their should be a list of any problems with carpet, walls, windows, ectra. If so yea, call the police, they could take you to court, but to change the locks, I do not believe they have the right to do that. If you gain access, take a camera, to prove the condition of apt. apon move out, for court should they go that far. Best of luck to you, I am thank full everyday for good neighbors, and to be out of an apt. They have probally been going through your home, when your not their for months. I'm glad you choose to move. I like the responce about taking pic'c with newspaper, to prove the date, good advice.