I have come to the conclusion that I have absolutely no idea who it is but I am going to very disappointed because I found out that it is Simon Baker who does the voice of RJ, which means it's a fake voice. I so wanted him to super creepy and spookay!! I wanted that to be his real voice. Most people who have encountered him for example the little girl, said that he had an odd voice. So ....from this we can gather that he does have an odd voice that is recognizable as being odd. Who has an odd voice..the only person that does is Stiles. None of the others are odd, and I can't imagine then being odd either... to be honest. 
Why did they kill Bret Partridge?? He was perfect. AND why did they kill off all the characters that would be ace RJ's? Even kirkland had a psychopathic look to him. I can't see someone like the sheriff being the RJ that we seen rescue Jane from the copycat killers. I can see Stiles but he is so old. Bret was the best one, failing him the ONLY other person that I could see working as RJ is RIBSGY! Those are the only two that would do him justice.

BTW, I know it's not him BUT season 1 pilot Partridge scene, did anyone notice that when Partridge was talking about RJ entering he ran into Rigbsy TWICE at the moment he said Red John....just saying would be awesome AND did you notice that Rigsby looked uncomfortable when Jane said that it was RedJohn?

I can hope can't I? :-(