I was thinking of that but to be honest, I've never used them, and the free ones online do not work. You could turn on private browsing in your browser, (I'm not a mac owner yet) but I'm not sure if Safari offers that. But Firefox and Chrome do. That might help with the browsing side. I might look into purchasing software or a subscription or however that works for a proxy. At least if you do decide to use it, use it for maybe a year or more to make sure he's lost interest if that works. I don't know how I would proceed if I were in your sitatuion but those are the things I would try.
I really hope the police nab this guy and put him away. I'm sorry you are going through this. I can't imagine how I'd feel. Though I did have a situation where someone sent an email in MY name (with a new email account they created) and (when I was just starting high school) and the person said they wre going to kill all of my friends including me. THe police caught the guy, come to find out he was a friend of mine. What a nightmare. But I can sort of understand how you feel, though it's not the same thing. I wish you the best. I hope you can fix this or at least help the police get this guy. *hugs*
Brittany