Good girl! It is never wrong to gather information. Chances are probably good that if you just kick him out and change the locks, he won't do anything about it but you never know. It's best to go about it legally so you will have the backing of the police if he gets nasty. I know this all sucks and it's sad that you have to worry about getting into trouble with the law when it's him who is doing wrong, but the last thing you need is to be forced by the police to allow him to live there for a certain amount of time if you don't go through the legal channels to get him out.