I pretty much went dark from the internet from saturday to monday so i didnt see any spoilers after i made my final prediction, I went with Ray Haffner. Now, I honestly have no idea who RJ is, I narrowed it down to around 5 people haha.

After last nights episode I have changed my mind for obvious reasons (death).

Last nights episode ended with Jane in a church and we see in next weeks promo that someone follows him into the church and Jane shoots him. This can't be Red John as thats supposed to take place in a park and surely they'll save that for the end of the episode, not the first 5 mins. I heard people saying it could be Judge Manchester (maybe leader of Tyger, Tyger) who could have signed the federal warrant we see at the end of last nights episode.
It could also be Tom McAllister who I believe survived the explosion. How was he the only one out of the 4 on the other side of the room that got burnt to a crisp? He could have smuggled that bomb in under his hat which was placed on the sofa where Bret Stiles and Ray Haffner were sat. I think it was McAllister who gets shot in the church and we later see running through the graveyard outside and through the window of someones house. But I have no idea how that relates to the RJ story if it is indeed Tom McAllister as the meeting with RJ would go down in a park later in the episode.
They said themselves in the episode trust no one as anyone could be in Tyger Tyger. So why should they trust the DNA results that came back. But McAllister was the only one who supposedly died but shouldn't have.

My guess for RJ identity is either Tom McAllister (which I can't really explain). Why would he meet him in the park later if they just met in the church earlier on. (Maybe he was the one ordered to kill Jane's family?)

Then there's Gale Bertram who has already been identified as Red John. I can't see it at all. When he killed the Bar Man, it was sloppy, not like RJ's careful precision. Why would they reveal RJ this week and make it so anti-climactic.

Final choice is Brett Partridge (yes, another Partridge theory, thats how lost I am.) Didn't see his face and every scene of importance seems to have the birds which relates to his death, and name)

Then again it could be anyone, Ron, Kirkland, Gandhi or Santa Claus. I can make cases for each equally.
Just hope for an epic finale to one of my favorite storylines.