I have no idea who Red John could be but here are some observations: In the final episode of season 2, we see the smiley face on the wall in Rosalind Harker's house. After carrying out a murder, Red John generally draws the face on the wall using his victim's blood. He didn't murder Rosalind Harker and as far as we know did not murder anyone in her house (unless I missed something!). If this is the case, whose blood did he use to draw the smiley on the wall? If Roy Tagliaferro (who may nor may not be a red herring!) stayed in the house on and off for five months, then his fingerprints and other DNA must be in the house and also on the mail box. We don't know if this was checked. If so, we would know if he worked for a government agency, CBI, FBI, etc. or not. In any event, after this RT's fingerprints at least would be on file. In seanson 4, episode 7, PJ set up Panzer to criticize RJ on TV knowing that RJ would seek revenge on Panzer and probably kill him. Why then, did the CBI not track Panzer to catch RJ? In the last episode of season 4, PJ is watching an animal documentary on TV in the motel room with Lorelei. At one stage, the lioness caught a zebra and Lorelei had to avert her eyes from the screen. Does it seem logical that someone who is too squeamish to watch an animal attack another on TV would be capable of trying to chop PJ's fingers off with a shears a day or two later? In another episode of season 4, they eliminated another murder suspect when it turned out he couldn't stand the sight of blood. The animal documentary (predator hunting prey) seems to be a recurring theme throughout the series. In the very first episode, PJ is watching a similar documentary in his hotel room. Also, Lisbon did not seem that scared on hearing the Red John wanted her dead. Even if she knew that PJ would not harm her, is it logical to believe that she would have taken the risk of going into the desert without adequate backup knowing that Red John would be there and wanted her dead? Would an experienced agent like Cho would have let her do this? A stickler for the rules such as Cho would have known that this would have been against procedures. In any other crime show, they would have been accompanied by a SWAT team, helicopters, cars, etc. Does this mean they knew it wasn't a real trap? Or was it a delusion/hallucination? Later on, when Lorelei is in the interrogation room, PJ goes over to her, puts his hands on her shoulders and kisses the top of her head. Apart from being a highly questionable gesture as Lorelei is now a suspect, would it be logical for PJ or any normal person to kiss somebody who has just tried to maim him (even if they had been in a relationship!). It seems to me that he either used this gesture to hypnotise her or to dehypnotise her if she had already been hypnotised. I believe he hypnotised her in the motel room to have her believe that she was working for RJ (PJ's smile as he closed the door when she left) so that PJ could have the CBI (for whatever reason!) think that she had lured him into the desert on behalf of RJ. However, the plan went wrong. Lisbon and her team got arrested and were delayed and Wainright got shot. PJ then had to dehypnotise Lorelei in the interrogation room so that she wouldn't talk. Time and time again, completely logical procedures such as tracking and fingerprinting are omitted from investigations. If the writers left such glaring omissions in the scenario, then it was obviously done on purpose. Are we really watching a real murder investigation or is the investigation a metaphor for something else? It is also possible that PJ's couch represents a mental institution or a psychiatrist's couch and a certain amount of the story is happening in his head. Assuming that they are really searching for a serial killer: I don't believe that Lorelei is RJ. I believe that she is a means to and end for PJ. However, it shows us the PJ is capable of using hypnosis or another type of manipulation to transform into a potential killer a person who would otherwise not be violent. If she could maim him then she could have also killed him. Given this, I believe that RJ could have been created/manipulated by PJ during his days as a psychic/hypnotist. Something went wrong and PJ does not know the identity of the killer/RJ. I believe that PJ is not RJ but PJ has something to hide. The CBI does not know this part and this is the reason that PJ wants to catch RJ himself so they won't find out the part PJ played. Maybe this is why the FBI are suspicious. I also believe that the Tyger Tyger poem as well as dealing with good and evil also deals with the predator/prey theme as in the documentaries. PJ started out as a tiger/predator/manipulating people (RJ?) (lambs) and is now a lamb/prey/manipulated by RJ. I think it is also certain that the writers would not run the risk of having the viewers become attached to any of the main cast members over several seasons and then reveal one of them to be a serial killer who murdered a child in cold blood. RJ is either a minor character or somebody we have not yet seen and could also be a woman. Brett Stiles would seem to be the most likely suspect but I think that would be way too obvious. However I believe that he knows the identity of Red John and probably Kristina Frye also knows if she ever come out of the coma.
