After having reviewed the background appearances of the Red Sweater man (http://www.youtube.com/watch?v=590v4FCm6WU), I feel like he could turn out to be RJ after all. In that scene the man pretending to be RJ talks about changing his identity and making a new life. Then, in season five we get Bob Kirkland, who looks allot like Red Sweater Man. I know that there are a couple of clues that would seem to disqualify Kirkland, but like the murder suspect in many episodes over the years, they could easily be explained. among the seven suspects, none act more like a serial killer than Bob, and he has also proven hat he has no problem with murder.
He may turn out to only be a RJ soldier, but he seems like the most likely suspect to me. I'll be disappointed if it's Haffner, if you look at his first show he in no way seems like RJ: both in his interactions with PJ and the way Bertram talks to him.

To those who suspect CBI Ron: Ask yourself, where was Ron when Red John painted his smiling face on Lisbon's face?!

i think bob kirkland is red john and he might be suffering from split personality

After the "Red Listed" promo, I'm completely stumped on how Kirkland could fit into things.  Little help?  I mean, consider:

He can't just be someone seeking his own vengeance against RJ, nor can he be a law enforcement guy just trying to find/catch RJ. If he was either of those things, he wouldn't have killed Lennon without trying to learn RJ's identity from him.

But he can't be RJ himself either, because RJ would have no motive for capturing & torturing PJ to get his real list of suspects.

The obvious alternative would be that he's RJ's ally (an enforcer or some such).  He killed Lennon to keep him from telling anyone who RJ is.  He wants PJ's real list in order to learn (A) whether RJ is on it, or (B) anyone else who could identify RJ is on it (and might rat RJ out if cornered himself, etc.).

But even that doesn't really make sense.  Because it's not like he could torture PJ and then leave him alive to tell how Kirkland tortured him;  he'd have to kill PJ once he got the info he wanted.  And certainly, RJ isn't about to let a mere ally be the one to kill PJ.  If PJ were going to die, RJ would want to do it himself.

So I can't figure out his angle.  Anyone have an ideas?  Please comment and share.  :)

                     I have a theory based on some notes
                                    let's begin...

"Robert Kirkland , Reed smith and Gale bertram are friends, i mean, one team".
     In fact:
In S05E05 "Red Dawn"
-alexa shultz with Robert Kirkland (in Limo) ask Virgil Minelli vie phone to keep her in loop about Red John's  case.

in other scene:
 Robert Kirkland is a "friend" of Gale bertram -may be just for work- anyway they both ask Teresa Lisbon if jane mad a progress on Red john case.

In S06E02
-in the meeting between 3 suspects : Gale bertram , Reed smith and Sheriff thomas mccalister, Reed ask Gale how jane is close with little authoritarian Voice.

Now we have two cases:

1) Robert Kirkland , Gale bertram and Reed smith cooperate with the aim of finding Red John before Patrick Jane find him.
    In that event, that let us think that may Raymond haffner or sheriff Thomas mccalister is Red John and is protected and invested somehow by Bret stiles.

2) Robert Kirkland is himself Red John and helped sometimes by his team Gale bertram , Reed smith and Bret stiles of course due to the fact that he was involved in "Visualize" and "the farm".

I hope that those things make a sense , and i think all fans and participants for their nice theories.

So looking at the promo for episode 4, i think it is clear that Rob Kirkland is not red john. He must be looking to kill red john himself in some sort of personal vendetta or just simply wants to catch him. He sure seems like he would do anyhting to get to red john (kill that guy at the hospital, torture jane as seen in the promo). But he got the fake list jane left in the room and he is going after the wrong people. I think now he has realised and thats why he tortures jane to tell him the real list.
I know promos can be deceiving but it looks pretty straight forward, i think we all new kirkland was tricked by jane, because jane smiled when he saw they had entered his room. But now it seems kirkland may be killing those fake suspects or something like that, thats why jane is worried and tells it to lisbon

I am still surprise some people are still suspecting Mcallister. A recent video was posted stating that the homeland security has been spying on jane for 9 years. Clearly the hints such as whistling was part of deception which made us believe that MCallister is Red John. Kirkland ends up torturing Patrick Jane in a future episode.