People i intend to think that RJ is... Ellis Mars!
Because: 
1. In the end of 1x11, Renfrew writes on the wall "He is Mar..."
2. He shook hands with Patrick
3. As fake "psychic", he know about Jane's tragedy.
4. And the most important; His business card has a red tiger face on it. And what poem did RJ quoted to Jane when they met in that basement? "Tyger Tyger"! A William Blake poem. 

Although, in the ending of CBI murder case, Bertram also quoted a poem, that Cho identified as William Blake's... And there is no doubt that Bertram works for RJ.