Sorry for my English, I'm from Venezuela.
This is not an accusation, but did someone remember the last episode of season 3?
There was 4 suspect on Laroche list and they make us think that one of them is the RJ accomplish, then the dispensable killer goes to the last floor with the intension of goin one floor down and kill Hightower. But there is a funny fact here, what is the dispensable killer was not going to go down just one floor down? What is all four suspect even including Laroche are connected with Red John and they all gave him the address so he could think send the dispensable killer to all floor looking for Hightower since he know all addresses or just sent the killer to Bertram floor so he could distract them for O'laughlin to kill Hightower and then sent Timothy carter to the mall where Jane met with Bertram since Bertram is also an accomplish of RJ he told him they will meet in that mall

I guess Brett Patridge is Red John.
- Many people are saying that Red John must have appeared since Season 1 and that he has to be one of the "three main characters". Brett appears at the first episode.
- Also, many people say that Brett always appears to "mask" Red John cases.
- His voice is very similar to Red John's voice at 2x23. 
- PJ always says that Brett is a ghoul. I'm sure PJ hates Brett. Then they aren't friends. Lorelei said that PJ and RJ aren't friends.
- Brett, in fact, is really smart (he just pretend he isn't). They say that equal people hate each other and the opposite attract. PJ hates Brett because he is just like him. Lorelei also said that PJ and RJ are very similar. 
- At 5x15, Brett talks about the "human torch". Possibly, it's the same trick that RJ used at 3x09.
- And at last, RJ is a thin and agile person (see 2x23) then he can't be someone like Minelli that is a little overweight and old (no offense to the actor).

The question is if Brett has a connection with Visualize, it would be the last evidence. Well, people say that PJ and Brett shook hands "offscreen", but I'm not sure of that. If they didn't, Brett can't be RJ. Sorry about my english, it's not my native language =(

We all know that Jane's goal is to find and kill RJ, that is a foregone conclusion. I pose this question though, what is RJ's purpose? If it was simply to kill random people or mess with Jane then there would be no reason for him to be associated with so many people when even one loose end could result in his identity being revealed and him being captured. I have a few theories on his purpose, because keep in mind he was killing people before Jane even mentioned his name on T.V. and his wife and daughter were murdered by him. 

1. He's like the Joker from Batman and just wants to see the world burn.

2. RJ is leading some sort of revolution. Its been hinted he was a member of visualize, and I believe he was Brett Stiles protege until the student surpassed the teacher and became dangerous to even Stiles himself. This leading to RJ needing a good number of followers to take down visualize and him having the techniques to do just that.

3. RJ ultimately wants power. He will do anything and everything to have control of as many different organizations as he can regardless of who he has to kill. Remember how he killed Bosco's team so Jane could be back on the case and the CBI just obliged and said OK. I didn't know that police organizations gave into criminal demands so easily.

4. In no way do I think Jane is involved in RJ's purpose or grand plan I just think that Jane got caught up in the middle of it with his comments and is one of the few people who intrigue RJ in terms of brilliance and so RJ toys with him. Don't kid yourself by saying Jane is smarter than RJ because time and time again he has been outsmarted and maneuvered. It's a game of cat and mouse RJ has enjoyed playing.

His purpose could be completely unrelated to any of what I just said and I could be completely wrong, however I feel as though it will be much easier to figure out who RJ is once his purpose or goals have been established.