Artsrun, we already debated this in the IRC, stop being an idiot.
Trace it. How do you expect someone who does not understand anything to trace anything? How would you trace the guy? What? You don't know? It's a shame, telling people things that you don't even know how to do.
Sue the guy? You're an idiot. He's not some multimillionaire company. Runescape items stolen. Right, lets go sue the douche who stole my pixels! Yeah! Totally! Idiot.
I think your idiocy blinds you way too often; stop being dense, and use logic.
You can't sue people for keylogging. You can't even go to jail for it. End of discussion.