I don't think Bret Stiles is the only Red John, but he is totally the brains behind the operation. My guess since the 2nd time the team went to Visualize (i cant remember the episode), I guessed it was a team effort.

I think Bret Stiles could easily be Red John, because he has that charming personality, and he also has the brains to do it. He leads Visualize, and I think that some of the people on the list of 7 (excluding McAllister, Smith, and Bertram) have been a part/are a part of visualize. We know that whoever Rj is, was a part of Visualize because of the Red Farm episode. Bret in my opinion doesn't do any of the killing (maybe the first few, but thats about it). I think that all the people involved with Rj have been a part of Visualize, because if they weren't then why introduce it anyway?

My theory is that Bret convinces the people to do the murders, its as simple as that. In S06EP02, the scene about Lisbon's Dream is useless, and that it's just another way Heller is trying to throw us off (like in S3 finale when Jane killed who he thought was Rj, but wasnt). I do think that Grace is also part of this team, but not from the beginning. In the EP03 promo, she gets married to Rigsby (the dude doesn't really look like him), this is something that will come in handy later on. I think she joined sometime before the S4 finale, where she killed Craig. I think that Craig was killed for Rj's sake. The thing that always gets me is that she has RED hair, and they are trying to catch RED John.

I think that in the Season Finale, things are going to get crazy. Rumors are that Rj is revealed on EP08, titled the "The Great Red Dragon" i believe. I think that the rest of the season will have really important people killed, some names I think of are J.J. LaRoche, atleast 4 other people on the list, one member of the team (most likely Rigsby/Grace), and also whoever Rj is.

Something I hope to happen in the finale is that Jane isnt the one to catch Rj, they lead this all up to think that Jane is the one that solves EVERYTHING, I think that Lisbon will be the one who gets Rj.

Bruno Heller confirmed that the meeting between Bertram smith and Mcallister has nothing to do with red john and it's related to the plot after the red john chapter ends which is related to law corruption and the two new regulars will have an important role to play in it. http://www.spoilersguide.com/the-mentalist/spoilers-what-you-should-know-about-bertram-mccallister-and-smiths-meeting/

First off lets talk about RedJohn. RedJohn is a genius for starters. He is able to manipulate people into doing whatever he wants.  Even to the point that they are willing to give their lives for him. He is essentially a God them.   He is able to get them them to believe that what they are doing is for a good cause or a higher purpose. So obviously he learned all that from being a member of Visualize. 
    I want to point something out to all of you phobia people. REDJOHN doesnt have a phobia of birds. His first smiley face was on the side of the barn thats in the middle of a field surrounded by a forest. I think if he does have a phobia its a phobia of being alone or caught. That would explain his joining visualize and why he didnt kill Lisbon. Another reason why he didnt kill Lisbon is because he has feelings for her and she is still useful to use against Jane.
    Now lets talk about the 7 suspects that are on the list.  
     Brett Partridge is not RedJohn. I do not believe he is the pidgeon lady or is still alive for that matter. Plotnik said Partridge is dead, Heller said Partidge is dead and Jane said he was dead. Brett Partridge is not Red John.
      Bret Stiles is not Red John. He is to old for starters and would have been recognized by Sophie Miller. Same can be said of Bertram. While Bret is intelligent he still needed Patricks help and ended up owing him a favor. Does that sound like Red John to you? Red John would never put himself in that kind of position. Never. Bret Stiles isnt Red John.
       Bertram,Kirkland, Reede, and McAllister are not Red John. They are all involved in a join effort to capture RedJohn before Patrick does. Thats why they all secret meetings and act so suspicious. Also a picture of Kirkland with Jane Zip tied to a chair was recently released. Why would he have Jane like that? Because obviously Jane knows more than what he's saying and Kirkland along with the other three want to know to.
    Raymond Haffner in my opinion is REDJOHN. Haffner other than Stiles and Partidge is the only one who hasnt inserted himself into the REDJOHN investigation. He knows Patrick is close so he's staying away from Patrick. That was the point of the nurse walking
into Lisbon's room looking for Carmen lee. Carmen Lee doesnt matter people. She was simply there to scout the room to let Haffner know when Lisbon was alone. Haffner fits the descriptions of REDJOHN given by Sophia Miller and Rosalyn Harker. Sophia also said he was a great whistler. Yes the other suspects whistled but it was Haffner who did it first before we ever heard that clue from Sophia. Haffner is a member of Visualize. The owner of a security firm and former CBI agent. Raymond Haffner meets all of the qualifications to be REDJOHN. Good looking, charming, has ties to Visualize, CBI, I think FBI and has his own security firm. Raymond Haffner is REDJOHN.