I'm not sure how they can be traced. If you received payments before, you *might* be able to see what address they came from and see if anything further has come from that address. But if he's clever, not only is he reading this, but he's not going to use that same address to spend them.
I think he slipped up with his t-shirt offering
http://i.imgur.com/wOdeaPf.png. Teespring is a US-based company and will comply with law enforcement to give up his information.
