No one suspects him? The quiet Asian guy? No one knows who he is, except that he is or was on drugs. His life is vague. Just a guess. The others are all red herrings.

to pick out of everyone of who i think RJ right now im sticking to Cho other then Rigsby or someone else why i think Cho is RJ is because i was rewatching the Pilot a few days ago and i noticed that when they were in the hotel and Patrick as given the note from RJ. flash ahead a few minutes and the rest of the team is in his room except Cho it is along shot guess

i also dissagree with it being Patirck Jane maybe he has an evil twin

and Rigsby just because he has the face to be a serial killer