In "Red Dawn," the 100th episode of the Mentalist, a mysterious man--later identified as Robert Kirkland of Homeland Security--sitting in a limo with FBI Regional Director, Alexa Schultz, appeared to have been following Patrick Jane
since Red John murdered his family. In "Red Sails in the Sunset," Bob Kirkland pursued Lorelei Martins, a Red John assistant, who revealed to Patrick Jane that he and Red John are much alike and she wondered how both didn't become best friends since the moment they shook hand. Evidence surfaced suggesting Bob Kirkland--who shook hands with Jane in a previous episode--is Red John. However, Jimmy Gadd, an editor on the Mentalist, confirmed that Bob Kirkland is NOT Red John and that Bob K. is a good guy with a story to be revealed in a future episode.

Robert Kirkland. Played by Kevin Corrigan. The first time he "ran" into Jane, was in the hall at CBI, he gave indication he knew Jane in an awkward fashion. Within the same episode, it is revealed by Lorelei that they've met.

Bob Kirkland.

In the E07 S05 - If It Bleeds, It Leads.

The episode ends with Bob Kirkland from Homeland Security talking to Lisbon and then greeting Jane in the corridor. The following conversation occurs: 
Bob: "oops, sorry Mr Jane."
Jane: "Do I know you?"
-HANDSHAKE-
Bob: "No... But I know you"
Scene ends with sinister music, high possibility it could be Red John, since Lora-Li escapes from Federal Prison in the next episodes.

Robert Kirkland (the homeland security agent)

1)Was the man in the limo at the end of Red Dawn that the woman was taking orders from

2)Knew Jane's name and shook his hand upon meeting

3)Shortly after we find out that Jane has met RJ and they have shook hands.

4)He has that talk with Lisbon about backing off

Robert Kirkland seems like an interesting choice right now. He was there in the flashback episode and after "If it bleeds it leads" seems even more mysterious. If the show does not get renewed I'd say its him and if it does get renewed he is a "friend" of Red John.

I think Red John is Robert Kirkland - you only see him twice in the show. He appears for the first time in Red Dawn. He is a friend of FBI's Californian chief Alexa Shultz. In If It Bleeds, It Leads, Bob Kirkland identifies himself to Agent Lisbon as a agent for Homeland Security and at the end of the episode he recognizes Jane even though he doesn't know him... 
Let's see on the next episodes but he looks very suspicious and creepy!

Robert Kirkland(Bob?? Not too sure what his full name is)..

2 instances made me think that this ''agent of Homeland Security'' was really the murderer. 

1.  Season 5 Episode 5 (Red Dawn)

At the end of the show, the director of FBI Alexa Shultz started chatting up to the first CBI director that we know of (Virgil).  She revealed to him that for the past year Patrick was in an asylum.  What purpose revealing this piece of information served for her or Red John, I dont really have much of a clue yet (perhaps to limit Patrick's points of access to information the CBI had on Red John by worrying the director? Or to motivate Virgil to keep tabs on Patrick as to how far he is with the investiation), but after hanging up she immediately she said "It's done" and faintly smiled at some man(Bob Kirkland) seated opposite to her.

He simply said 'thank you' in a soft, noticeably chilled voice. You could easily imagine his voice and Red John's voice being pretty similar.  Furthermore, I believe that conversation between Alexa Shultz and this Bob Kirkland, was pretty suggestive of him being some senior officer in relation to Alexa Shultz. I may be somehow wrong about this but what is this guy doing with a HomeLand security badge later as we see in episode 7?

2. Season 5 Episode 7 (If it Bleeds, It Leads)

PJ: " Do I know you?" 
Bob: "No.. But I know you"

His encounter with Patrick seemed pretty intentional frankly speaking. And all that sortof eerie background music... A bit suggestive. Also, while speaking with Lisbon, he seemed a little uncomfortable with his posture and he was stuttering a little in the beginning...


I'm not saying it absolutely has to be him Robert Kirkland, but if I were to guess based on all the things that red John has done, Bob Kirkland really seems to act like him.  And I wouldn't really bet on Volker (the threatening rich guy) being Red John.  Red John isn't as obnoxious as him, frankly speaking.  And he wouldn't really go around to people like Lisbon and start conversations that basically led to Lisbon doing her best to hunt him down... Red John's seems much more careful than that.  Furthermore, the manner in which he killed his assistant was ruthless but not really Red John's MO/style...

All in all though there seem to be a few problems with Robert Kirkland aka. Bob to be Red John.

1. Why is he so suddenly asking Lisbon out for coffee? (just seems weird) (S05E07)
2. Why is he suddenly insistent on protecting Volker? (maybe Volker is a part of Red John's way of protecting himself)