I think it's Robert Kirkland. We saw him in 4 episodes only, and yet each of those four brought an important twist to the story.
He was the person in the car at the end of the episode 5.05,
he was there when Lorelei escaped,
he prevented Jane from driving in the ambulance in 5.16. and thus possibly finding out the RJ's name.
I'll see if I can find other indications, but my hunch is that RJ might be Robert Kirkland.
I think that after episode 5x16 it is 100% sure that Patrick Jane cannot be Red John. If he was then Lorelei would have killed him. She had the means and opportunity. He is NOT Red John. End of story.
Why else would Bertram have homeland work on it? He knows PJ was getting close. He sent Kirkland to make sure that Jane doesn't get on the ambulance with the guy Lorelei shot. And he killed off Lorelei so she won't tell PJ. She probably had a note or clue which he hid as well.
I am sure it is Virgil Minelli. His original character name was supposed to be RJ patel. He retired at a time when bosco and others died to give Patrick Jane the freedom to investigate. In the recent episode, it is revealed that Miranda (Lorelei's sister) was killed with a fisherman's hook and it is shown that Virgil after retirement was a fisherman. His physical description, power within CBI etc. proves that he is Red John.
The crime scene investigator from the pilot episode and others is "RED JOHN". He is in the perfect job to secretly control murder investigations since he collects the evidence from the scene. He is the right build as "RED JOHN" when Patrick meets him in the copycat episode. Patrick already meet him a couple of times and he clearly states "he urks me!" I say he is "Red John".
After s5 e16 it must be homeland security officer Kirkland, why would he want to have info to Lorelei's case. If it is not him then red john must be a member of the us government because only such a person will have more power and resources than Kirkland.
Red john must be Bob Kirkland as seen in s5 e16, why else would homeland security take interest in Lorelai's case. I wish they would just reveal red john the suspense is driving me crazy.