Um shouldn't the pony and der tiny paper frog be on the suspects list?! WELL THEN, lets get started. The pony and the frog. The perfect team. The pony tramples the victim (pony has spikey feet and is imortal) and the frog paints the the toe nails and then stands on the ponys now inlarged head and paints the smiley face uses his boingy powers. BABAM, we're brilliant. You're welcome. ;) we out

RJ has started to play with Patrick now, I don't think that the carnival stuff at the scene of loreleis murder is a clue to RJ, but that RJ is now starting to frame patrick, gale Bertram and Kirkland were spotted talking about the cbi team, and asking if they could trust Lisbon. I have a feeling that Bertram and Kirkland think Jane is RJ and the team are following his orders. The real red John will be revealed and noone will believe Jane because everyone thinks it's him

Dean Harken is Red John, period. Dean Harken, the CDCA guy from S02E16 "Code Red".

He fits RJ's profile perfectly. The very first time I saw him I thought "Damn, he would be the perfect guy to play RJ". Besides PJ is a little suspicious of him too. You can see that in his reaction when they had first met and shook hands. PJ asks him for an ID and is surprised to see his ID with no photo. This is clue number one.

Now, as quoted by Teresa Lisbon, CDCA is Rich, Mean and well connected and in comparison, CBI is like the poor orphan. This would explain why RJ have ample resources and is well connected with both CBI and FBI. This would be clue number 2.

When Lisbon tells PJ how well connected CDCA is and they need to cooperate with Harken, Jane says he irks him. PJ must have have sensed something on him. As you know both PJ and RJ is good at looking right through people and see what's inside. Clue number 3.

In S05E09, Jane asks Lisbon specifically about the "Red Headed" security guard at the Bio Research Lab, Dean Harken. Of all people Jane have met, why would Bruno care to add Harken's name into the script for the second time. Obviously, the 4th clue.

In S05E09, in the last scene where the camera focuses on Jane's Book of possible suspects, Dean Harken's name is boldly visible along with some others. So he is definitely a possibility and this could be the 5th clue.

Besides, his age and physical stature fits RJ's profile. This is not a clue but just an observation.

In the episode Redacted Jane has a brief interaction with a man who calls himself Detention Officer Odonnel. Jane and this character SHAKE HANDS and then Jane tries to hypnotize the man WITHOUT SUCCESS which is very eery to me. If anyone has seen this episode and has an opinion as to whether Detention Officer Odonnel could be Red John or not let me know! JBP

People i intend to think that RJ is... Ellis Mars!
Because: 
1. In the end of 1x11, Renfrew writes on the wall "He is Mar..."
2. He shook hands with Patrick
3. As fake "psychic", he know about Jane's tragedy.
4. And the most important; His business card has a red tiger face on it. And what poem did RJ quoted to Jane when they met in that basement? "Tyger Tyger"! A William Blake poem. 

Although, in the ending of CBI murder case, Bertram also quoted a poem, that Cho identified as William Blake's... And there is no doubt that Bertram works for RJ.

I've no idea who red john is as I think the creators still haven't decided.
One thing I was thinking was can we even be sure that it was even the real red john in the mask at the end of s2E23 it may well have been Timothy Carter again acting on his behalf & not the true red john as many think.
Which pretty much shows that they can at any time say actually who you thought was red john was actually someone acting on his behalf & until we really get much more concrete evidence & scenes with an undeniable "true" red john, in which it can't be denied it was really him, it's pointless making a definitive choice as to who you think red john is!

Robert Kirkland is so Red John. All of the descriptions of RJ fit him perfectly. Also we know that RJ has "a friend in the FBI" and on the first episode with Kirkland a female FBI agent, whose name escapes me, said " it's nice to have a friend in the FBI, don't you agree Robert?" I cannot be the only one who thinks this.