This is just summing up what everyone else has said, but legally (as I have studied law) as long as you have told him to cease then you have the right to file a complaint. If you have told him to stop, and told him no, then you have every right to talk to the police. However, they are going to want you to stay completely away from him. No friendship, no projects together, and certainly no being ALONE together. They may even think it is in your best interest to file a restraining order, as even reporting the behavior may not stop him. I do think you should tell someone, and then do as they say and stay away from him. If it continues to happen he will be legally responsible and charges can then be filed.

Wish you all the best and hope you're doing okay.