since no one is answering your question, let's ask again: How did they find out who he was? what prior post of his revealed so much about him, that he could be identified?
Someone suggested that a look at a freepers "in forum" comments would ultimately reveal who he is. Buckhead, for starters, is a place in Atlanta. That he's a lawyer would also be revealed by his posts. Other than than, I don't know how the investigators figured out exactly who he is.