Obviously, the hacker was starting to feel the heat of being scrutinized so much and worried that the mixing funds might get frozen somehow.  I really think that klee should man up like Roger Ver and leave no quarter for the scum.  Taking a token from him only condones that the behavior pays off.  It is time to turn up the heat now and not kowtow.  You have another bit in the puzzle in that the email service (albeit anonymous) might have an IP to go with the hacker. Every lead counts.

My vote is fry him, he is already nervous, don't let him sleep well at night.  Remember mister hacker, not everyone is silly enough to tip you off by posting in a forum.