What a freaking psycho. Good riddance.
Hopefully you're right and he'll knock it off soon, but if he doesn't I wouldn't hesitate to call the police. In the meantime keep track of the times he tries to contact you and such. It's good evidence just in case.
And I wouldn't deal with him at work either. I broke up with an ex I worked with and he went really crazy (stalking, breaking in to my house, threatening to kill himself, etc) and I didn't associate with him at work at all. Of course, it helped that my managers saw his crazy behavior and stopped scheduling us together.