I would let him know in plain english that if he contacts you again in any way shape or form you will go to the police and then follow through. Make copies of all his e-mails and take them to the police. Contact your friends and co-workers and let them know what is happening. Give people a photo so they know what he looks like and to be on the lookout, ditto with his car. This is not someone who is playing with a full deck. And yes I would change my e-mail address and phone number ASAP.