I chose using this signs:

– It is likely a known man to PJ
– This man may appeal to PJ, they are possibly much alike
– This man has to have appropriate means and abilities
– And couple other signs

My list of possibilities on the RJ role:

- Ellis Mars (unlikely in my opinion, but possible)
- Tolman Bunting (seems possible)
- Dave Martin (although we never met him apparently, maybe he is someone from PJ's past life, maybe he is someone from the list)
- Walter Mashburn (apparent reasons)
- Dr. Royston Daniel (has very powerful abilities)
- Red Sweater Man (seems unlikely that his appearance is random)
- Nate Glass (seems to me as one of the most probable possibilities)

Also:

- The writing on the bathroom wall made by Jared Renfrew in blood I think means "he is mark", since there is no need in "he is" if he tried to write a name, no need to waste the time
- Mysterious cousin Yolanda of agent Grace Van Pelt is very suitable possibility on RJ's role (not necessarily being a woman, but Van Pelt's belief in her powers is quite suspicious; also fits in theory that some Van Pelt's relative was PJ's mark from his past days)