will I be in trouble?

I am now in Detroit. A terrible event happened in my apartment and the response of the landlord to the event was so indifferent and unconstructive. I no longer feel safe and plan to move out soon before the lease is over by the end of October. However, the landlord asked for rent of the remaining three months. I don't want to pay for it since I don't think it is I who breaks the lease. The following is my story. I am wondering whether I will be in trouble (bad credit, or being sued) if I don't pay for the remaining rent.

About 7:40pm, July 19th, 2005, I noticed a pair of footprints on the wall of my bedroom. The door was not broken, nor were the windows. I know there were no footprints when I first moved in. Every time I leave my room, I lock my door. The door was locked when I came home that day (July 19). I did not give my key to anyone else. The only possibility is that someone who has the key to my door entered my room in the daytime and left his/her footprints on the wall Monday or Tuesday (i.e., July 18 or 19).
After I noticed the footprints, I informed the manager of the building. The response I got from the manager was that the footprints were not his and that he could send someone to clean it up the next day. The next day, around 10am, I informed the landlord, and showed him the footprints. What I got from the landlord was that they had changed the lock before I moved in and that only three people had the key, he, the manager, and myself. The landlord did not mention any solution that could make me feel a little safer if I continue staying in my apartment.
I have not stayed in my apartment over night or cooked since the footprint event happened. I do not feel safe. I feel it is the landlord who is breaking the lease because the landlord can not ensure my safety when I stay in my own room.
I sent a memo to the landlord and told him I am going to move out by the end of July and that I will not pay for the remaining rent. Do you think I will have any trouble with this? Will this impact my credit? Will I be involved in a lawsuit? Thanks a lot.

Best,

ran