Someone mentioned a while ago that Brett Partridge might have had a twin brother. This was their explanation for two things. 1) How Brett could fake his own death, as his twin would have near matching DNA, finger prints, etc, as him. 2) How the producer of the show could say "Partridge" was dead and not be lying.

The whole twin thing fits in with the idea of symmetry throughout the show (Tyger Tyger). In William Blake's painting Brace of Partridge there are two birds, both mirror images of each other.

Perhaps Red John has some sort of fascination with twins. Robert and Michael Kirkland, whose lives he ruined. Lorelei Martins and her twin sister Miranda.

His obsession with this "symmetry" could be because he is a twin himself.

Just a theory.

Here is a wild theory that popped into my head the other day.

Brett Partridge has always been the number one suspect for good reason, because Brett Partridge WAS Red John.

He is really dead. He was killed in Episode 1 of Season 6 by a new unknown killer who may or may not be a Tiger Tiger member.

We will see the other suspects all be killed off or eliminated from being suspects (even though they have shady aspects to them) as the truth emerges that it was Partridge all along.

This moves the show on to a new era with the question changing from "Who is Red John?" to "Who KILLED Red John?" and how should Patrick react to the killer who was able to "get" Red John and rob Patrick of the chance of vengence (which is what has been driving him for years).

The killing of Partridge did not seem like a Red John killing, especially with what happened to Lisbon. Have there been any confirmed Red John killings since Partridge died? The Lorelei video suggested that he would be going on a killing spree, but that has not happened.

Okay. So at this point, we all know that Heller has told us about a key clue in the final sequence of 6x01. It could be the writings on the wall, the pigeons, the way Lisbon fell, really it could be a huge number of things. But what if it was the fact that RJ had both hands occupied, one holding the knife and the other painting blood on Lisbon's face, while making the call to Patrick? Some people are saying that this means the call was coming from somewhere totally different, or that an accomplice of RJ was painting Lisbon's face with blood while RJ himself made the call. But we have to remember that the call could only have come from inside the house, since RJ used Lisbon's phone. And another thing, even though it looks like both RJ and an accomplice were in the house, that isn't necessarily the case. People are assuming that RJ couldn't have made the call himself since both his hands were already busy, and for whatever reason, nobody thinks of the fact that he could just be using a wireless headset with the phone. And, if you re-watch 1x01, who do we see wearing a wireless headset? Brett Partridge. And the headset is in his right ear, where he would put it if he's right handed. And, from the last scene of 6x01, we see that RJ is right handed. 
Also, someone pointed out why they think Partridge said "Tiger Tiger" to Lisbon. This big organization of corrupt law enforcement agents that uses "Tiger Tiger" as a secret password, from what we've learned, specializes in unity, teamwork, and cover-ups. Maybe Partridge said "Tiger Tiger" to Lisbon because he was looking to see if she was part of this organization, so then he could ask her for help in covering up his death. But since she didn't respond back with the password, he fakes his death in front of her, and proceeds to knock her out and paint the more clown-like RJ smiley on her face. Partridge, if he is RJ, didn't kill her for one of two reasons. Either something spooked him because of his phobia, or he was trying to send a message. The message with the face being more clown-like could be RJ/Partridge saying that he finds it a joke that somebody that isn't part of the "Tiger Tiger" association could come so close to Red John and not even realize what is right in front of them. If there was a second person in the house, a RJ accomplice, they were probably hiding in the room that Lisbon looks at after Partridge "dies" solely to be a backup to help Partridge with faking his death just in case Lisbon isn't part of the "Tiger Tiger" organization and thus couldn't help him fake his death.
There just seems to be too many clues that point to Partridge being alive for him to truly be dead.
Maybe "Partridge" as an alias is dead, but not Jack Plotnick's character (Red John). Then, Plotnick and Heller technically weren't lying to the media in their interviews.

Not a theory, just a question: Could Partridge's "Tiger, Tiger" been the "big" clue in the first episode? Couple with episode 4's revelation, I wonder. What was he telling Lisbon and what exactly did she do about it?

I don't know but will be interesting if Rigsby was Red John as will be quite dull if was Haffner, 

Brett Partridge is hiding red tiger in his name. Is that a clue? 

Will be interesting if it is him , definitely is not Patrick or Lisbon .

Hoping for a good twist, happy if is the wicked twin.

So I guess 1.- Partridge 2.- Rigsby. 

I want to find some more codes !!!

Not so much a theory on who RJ is, but rather some observations.

1.  When Kirkland killed Jason Lennon, he asked Lennon if he recognized him.  This clearly shows that this was BOB Kirkland, desperately looking for someone with a connection to his twin brother.

2.  When Kirkland kills Jason Lennon, Kirkland describes himself as a "friend" and the killing seems almost compassionate in its execution.

These 2 things seem pretty incongruous from what we saw of Kirkland in last night's episode - someone out to destroy Red John for having taken his twin brother away.

Now we don't know if Michael Kirkland is still out there somewhere, but I think that observation #1 above pretty much rules out him being the one that killed Jason Lennon.

As for who actually IS Red John, this is just a theory, but let's look at some possibilities:

Bret Stiles COULD be Brett Partridge's father.

Bret Stiles COULD have all kinds of influence and connections through Visualize members within law enforcement - enough to influence them to provide SOME protection to his son.  He could even have some pull through the "Tyger Tyger" organization.  Pull that his son could easily be aware of.

These connections and influence COULD have been what Partridge was looking for when he said "Tyger Tyger" to Lisbon as she found him - looking for some assistance in faking his own death.  When such assistance was not offered, he tasered her when she looked away.  The next law enforcement to arrive responded affirmatively to Brett Partridge's "Tyger Tyger" reference, thereby assisting him in faking his own death.

If you watch the episode where Brett Stiles helps Jane rescue Kristina Frye, Stiles seems genuinely concerned with stopping, but not necessarily catching and punishing Red John - the way a father might want his adult son to stop behaving badly, but also want his son to avoid what the father considered too harsh a punishment.

So my overall theory is that Brett Partridge is Red John.  He is Bret Stiles' son and he has used his father's connections to protect himself, though he is not without the power of persuasion himself.  He uses his fathers connections but sees himself as ultimately surpassing his father in importance (as do Red John's followers).  This also explains his need for attention, his need to make the Red John painting the center of every one of his crime scenes.  As the son of a cult leader, he could never HOPE to garner such attention himself, so he tries that different tactic to get the attention he so desperately craves.

Well it's either Haffner like I mentioned a few weeks back, or will there will be a Twist? 
Perhaps Partridge didn't like the way Jane starred at him, at the beach? We know the Tyger Tyger organisation can perform cover ups and we all know Red John is rather theatrical... 

Perhaps one of his minions tasered Lisbon whilst he faked his own death? Never tested the blood on Lisbon's face to confirm it came from Partridge, as Jane wipes it off immediately...

Just my theory, either obvious Haffner as he meets both Rosalind and the dead shrink's descriptions, or a bit of a twist with Mr Partridge. (breTT, TT for Tyger Tyger? Letters in his surname can spell red)