Posted 13 December 2008 - 01:13 PM
The only thing I can think of is you could get a law enforcement agency to submit a subpoena to Microsoft. Unfortunately this legal recourse would probably be a futile attempt because if the person was on a large ISP, the IPs he had used would not necessarily locate him geographically. Your other question about finding out after the fact, there is not away to figure out where he is after the fact that I know of.
Maybe in time he might contact you again. If he he emails you, you can definitely see his IP in the headers (assuming he doesn't use proxies on his end). I wish I had better information to offer you, your situation is sad to read about.