I think the first order of business would be to contact the local police, next I would most definitely try to get a restraining order. As for the lawsuit against him, if he has nothing to take then you are just going to spend alot of money to take him to court, and get nothing from it.
Also if you get a restraining order it may also include a non contact phrase, meaning if he calls you or emails or sends a letter he is in violation of the order and will be arrested.
Good Luck Billet