No one will give you the definite answer you are looking for, and most of us have probably struggled with the same thing you are going through. Best suggestion I have is make sure your MD5Tool list is current and have ss capture on. Streaming is beneficial to the community if he ever does get caught. Another thing you can do is get demos of him/her and privately ask some others to review them after you have viewed them yourself. You should not be selective about your demos, meaning don't ask someone's opinion of demos that seem obvious and ignore the ones where he actually gets nailed a few times.
I'd be happy to look at any demo you have of him/her, though I'm no expert (no one is). If you want to share his last 8 characters of his GUID (PM me), I'd also be happy to let you know if I have anything on him/her as well.