just one clue, just for open a new conversation, I thing that in the 6 season will appear again sophie miller cause she made the tratamiento psychiatric treatment, I guess that she knows all the life of Jane... may be she's a tool of RJ.... I pick brett partrige just for picking a name, I don´t know if is connected to Sophie Miller

It's totally Brett. No other choices.

Not sure what to make out of this image of Jane, Lisbon, and Brett... 

http://wwwimage.cbsstatic.com/base/files/styles/596xh/public/103556_d0864bc.jpg

Full gallery from the new season (not many), http://www.cbs.com/shows/fall-previews-2013/photos/1000674/the-mentalist-first-look/

I have some arguments for accusing Brett Partridge.

1. In  Series 2 eppisode 23 there is the scene where Jane meets Red John with a mask. His voice sounds very much like Brett's
2. I beleive that in series like this, the director always tries to inject some subtile details in the filming. No frame or scene is accidental. In Season 5 finale, at the beginning of the eppisode, where Jane arrives at the crime scene, there is a close-up on Brett with Red John's smiley in the back. This illustrates that Brett could be Red John. The scene is aprox at 2:55.
3. In the same eppisode he speaks about Lorelei Martins and gives details.
4. Brett is a forensic investigator, a job very conveniable for a serial killer. He must be in the action.
5. He is thin, thick voice, strange attitude. Usually is boring for a serial killer to be strong and bald, like Gale Bertram.

My opinion is that in a clever series like "The Mentalist" the killer is either every time in your sight(Patrick Jane, Teresa Lisbon), but you don't suspect at all, or he/she appears in few eppisodes and this appearance must give subtile clues about him.

While looking thru short clips related to the list of 7 suspects...it suddenly dawned on me something that I think we've all overlooked or misidentified since the very beginning.....it's been believed mistakenly for a looong time that Red John's infamous sign of his work was of extreme likeness to Patrick Jane's face....but upon looking back at several clips of him....one will see an amazing likeness to Brett Partridge's face in cartoon form.. especially when he was excited and smiling widely while demonstrating with the golf club from the first season episode...it would make sooo much creepy sense for him to be signing with his own face that he sees in his mind's eye with each of his killings....

Patrick Jane hates Partridge and he call that name "ghoul"  , he plays down Partridge's intelligence

Season finale, RJ has send to a message, " I show you god damn clever." 

Partridge just not a Forensic Technician.


He is a mastermind, he is Red John. 

Conclusion after some research on here plus personal opinions.

Bret Stiles is the father of Raymond Haffner.

Robert Kirkland is not working for RJ nor he is RJ, he's hunting RJ cause he's mostlikely the boyfriend of Miranda.

Brett Partridge was the original RJ but Bruno Heller kept going cause show got popular so RJ could be changed now.

So.. RJ could be one of Haffner, Partridge, McAllister imo.