Well sorry to bring this post back up. I am off to change all the locks on the house. I was advised against it by the property managment company, but I did call the Sergent just now and double checked with him to make sure I would not be in any trouble criminally if I did so. He said there is no law stating you can not change the locks if you fear someone.
Although through a legal standpoint I could be liable in small claims court I believe.
Hope I'm doing the right thing...I'm afraid it's only going to make him angrier at me...