I think RJ is Kirkland, but Jane has been thrown off the scent because he doesn't appear to have shaken hands with Kirkland.

However, when they shook hands in the past, RJ literally had a different face and did not look like who we now know as Kirkland.

Clues:

1) Do you recognize me? (as Kirland carefully shows his face to the guy he kills in the hospital bed) No? Good. (then calmly injects the needle into the IV).  His voice almost sounded like Christopher Walken, so maybe Christopher Walken is RJ :-)  j/k

2) The woman in the hospital remarks how the guys from Homeland Security are creepy, not who they appear to be, like aliens under the skin.

3) The fake RJ that Jane killed at the end of Season 3 told Jane that he was going to stop killing, get a new face, new identity and move on.

I have watched this show from the beginning and people come up with the most ridiculous ideas. Seriously do you really think that Red John was some disfigured person who killed Robert Kirkland, got radical facial reconstruction and took his identity. ARE YOU KIDDING ME? Why?? For what purpose. Red John is smart and savvy enough to brainwash someone, get people to KILL PEOPLE and KIDNAP PEOPLE FOR HIM and his is SERIAL KILLER but then says thats not enough I need to take over someones identy and he gets RADICAL FACIAL RECONSTRUCTION. PLEASE. People try to mold certain things to wrap around their theories. What is more possible that Kirkland knows Red John (we all know that RJ has someone high up in government who could be Kirland and Kirkland is the same guy in the limo asking for updates on the RJ case from Minelli) and could have been in a picture or something where Lennon would be able to identify him or Kirkland is RJ and went through radical facial reconstrution. I am sorry I just dont it for a second.

Also think about it for a second instead of trying to parse words on what you MAY think each word means. If you think someone may or may not have seen you a few years ago in a picture or in a previous meeting and could give you up wouldnt you ask them if they recognize you to see if they had said anything. That makes senses. What doesnt make sense is  RJ got radical facial reconstruction JUST to be involved in a case so he could ask the guy if he recognized him. Why would Lennon recognize him if he got facial reconstruction and was using a different voice which I find extremely hard to believe? It makes no sense. I was just waiting for someone to say something something radical. Like I said I go back to what the creator and producers say about RJ instead of trying to invent theories. I still am sold that on the season finale we will find VERY SPECIFIC THING that will COMPLETELY CHANGE the way we search for RJ. Remember PJ has a very unique skill set to be able to search for RJ. What SPECIFIC skill set is that? He is a Mentalist/CON MAN and worked at a carnival. The last episode is at a carnival and introduces two new characters. I think we can all sit here and come up with wild theories but considering how big of a reveal this is and how the creators and producers have consistently thrown us off I just dont buy into Robert Kirkland being  RJ. Now I certainly think he is involved but not RJ and certainly did not get some radical facial procedure. So ridiculous.

It's his father. RJ calls PJ his "greatest creation". Mind Blown!!!!

Hi folks :) First of all: RED JOHN is NOT Robert Kirkland ;)
Come ooooon, it would be toooooo easy

My opinion:

Robert Kirkland was very eager getting involved in the Lorelei Martins- case. I think, Kirkland hypnotized Jason Lennon some time ago, so he could tell Lorelei about the rape and the following murder of Miranda commited by Red John personally.
When Lennon answered his question, if he remembers him, with "yes", it was obvious he had to kill him, to prevend Lennon from accusing him.

Maybe Kirkland was behind the murder of Miranda, but i think that would make him the next target for Red John

What do you think? :)

(Sorry for my bad english, im not from the U.S.^^)

It can't be Jane because it would damage the character for syndication.  Granted, it might be "neat" & make headlines, etc.; but - in the long run - Jane can't be a serial killer w/o damaging the series' potential revenue in syndication.  No one messes with syndication.  It's probably someone insignificant so they don't damage their revenue streams.

Red John is Agent Kirkland.
In season 5 episode 18, he kills the witness who knew Red John, and before that he asked him: "Do you recognize me?"
When he is asked by Lisbon in an older episode (season 5 episode 13) if he was at the Visualize farm, he doesn't answer.
He is the only person whom full name is unknown, so it's probable that he is Red John.

This is not a theory about who red john is, but something that I noticed. Bruno Heller is giving all the suspects of being RJ as the theories all over the internet more roles in the past few episodes. My guess is that he is revealing RJ this season.