Here is my theory. Please read all.

I improved my previous theory.

I think CBI Ron is real Robert Kirkland and he is Red John. At the Red Barn, Robert finds his twin brother Michael who tries to get rid of his alcohol issue, but now he becomes a drug addicted. Robert kills the other members of the Visualise. The problem is now how to prevent the Visualise from killing Michael. Michael is the weaker sibling and cannot survive against the Visualise. The twins switches their identities. Then real Robert disappears and Michael (now Robert) hears no news from his brother. What Michael does not know that his brother had a plastic surgery and changed his face and identity. That is why he did not kill anybody for a decade.Because creating a best identity theft takes years (in one episode an Irish guy who creates fake identities told so). Maybe during these years he kills under different alias like Roy. After a decade, he becomes CBI (R)ed j(O)h(N). This also explains why he is not on the list. because his fake identity does not fit the Red John case so Jane eliminates him.

This theory explains many things.

He is there from the beginning.

He is like Waldo.

He is really on the list (Real Robert Kirkland)

He fits the expression of Simon Baker. ( He told the interview it is like killing a family member). Unlike the seven suspects, Ron has been there in many episodes from the beginning.

He is close to Jane and the investigation.

Other things

He is mar. He is (M)ichael (A)ka (R)obert

Examine carefully Robert Kirkland (actually Michael). He has self-control issue and shaking hands. He is an old addict. He was desperately looking for Robert. That is why he ask people "do you recognise me?". He wanted to know if they had met Robert. He did not know for sure that Robert is Red John or his tool killed by Red John. He actually brought those people to his own cabin.

Ron had a phone at his hand when Jane came to the CBI at the end of episode one of season six. Then he called his accomplice who killed Partridge and while his accomplice was drawing his mark on Lisbon's face, he spoke to Jane through his accomplice' and Lisbon's phones. He kept it short because he did not want Jane to understand he was talking to him through two phones. In this way, he also eliminates himself as a Red John suspect in the eye of Patrick and many viewers. However, we know Red John tricked Jane before in this way (Think about Wainwright in the limo). Besides, when Jane staged the fake death of Rigsby, who were there with Wainwright? Ron and Karl. He could easily kidnap Wainwright and trap Jane. He is a good observant like Jane. He can easily notice that man is not Rigsby.

When Tyger Tyger killed his brother (They did not know the real identity of Red John and Kirkland is his brother), he gave tattoo clue to Jane to led him to kill the group members who are also Red John suspects (Bertram, McAllister and Smith) or he led Jane to bring all suspects together and wanted to get rid of them all together if he is the one who planted the bomb. In this way, he would kill both his brother's killers and the Visualise leader that is after him because of the Red Barn incident.

Lastly, I think Ray Haffner is the accomplice of Red John. he has a problematic childhood. He told so. He has also interest in Lisbon. He is a good tool for Red John. Red John always offers his accomplices the things they do not have. (As we know he offers the accomplice the girl he loves, in another case, he gives the baby) I think Haffner is obsessed with Lisbon and helping Red John to get Lisbon. It was Haffner who killed the fake Red John killers and saved Jane. Ron (real Red John) spoke Jane through the phone. He is also the one who drew the mark on Lisbon's face. If Red John is the one who planted the bomb at Jane's house, he also wanted to kill Haffner because he knows him. Red John has no friends, only tools. I really wonder what would happen to Haffner if Red John put the bomb.

After the loss of his brother and cleaning in the California Law Enforcement, he will desperately seek the friendship of Jane. then, bang! Bang!