Man, I feel for you on this. Find his IP and block it. If that doesn't work, block his entire ISP with a message that they have this guy to thank for it. Finally, ignore him. If he makes a comment, delete it. Don't respond. From what I've seen, you seem to be feeding into his pathology. This isn't a blame the victim thing, but an Internet thing. The guy's a troll and every time you answer him, you reinforce his behavior.