We know that Red John is very capable at creating fake or alternate identities. We've seen it. In the past he's used anagrams of 'Red John', or 'Jay Roth' where 'Roth' is a foreign word for Red. So, if Red John can create fake ID's, surely he can fake his own death, yes?

In episode 1 of Season 6, we see Lisbon follow the phone trace of Brett Partridge to an abandoned house. Upon entering, she finds Partridge bloodied and bound in a cupboard. After uttering the words 'tyger, tyger' he dies. Lisbon steps back, before being grabbed from behind by an unseen assailant. 

What would you do?

Imagine being Red John. You know Patrick's list, you know who he suspects, and you know you're on it. Surely the first thing you want to do is divert suspicion away from yourself. What better way than to 'die'? By taking yourself out of the game, you're forcing Patrick's hand.

I believe this is what Brett Partridge has done.

Brett Partridge IS Red John. Here's what happened....

An accomplice of his helped him by tying his hands together and covering him in blood to depict that Partridge had been attacked. While Partridge was bound and kept in the cupboard, his accomplice was hidden in the house, waiting for Lisbon. It was imperative that Lisbon saw Partridge 'die', or the whole ruse was for nothing. Once Partridge 'died', his accomplice grabbed Lisbon.  

At this point, Partridge would have come round, while his accomplice (presumably) drugged Lisbon. Partridge then would have killed the accomplice and used his blood to draw the face on Teresa. Being able to create IDs and modify records, Partridge may well have changed his DNA/dental information on record to match the accomplice who he killed. This way, once the body is taken away by the paramedics (which, by the way, you only see 2 paramedics wheel away a body in a body-bag, you never see who is in the bag) it can be identified as Brett Partridge.  Partridge escapes the house once he kills the accomplice.  Patrick would have been told by the hospital the body matched Partridge's DNA, and in turn he confirmed to Teresa that Partridge was dead. In closing, Partridge is now presumed dead, with the list down to 6.

The P.I., bugging the CBI office, and Kirkland

We know why Kirkland was after Red John. We don't know for sure if Red John killed Kirkland's brother, or if in some horrible (IMO) turn of events, his brother will turn out to be Red John (hopefully not).  I believe the 'Tyger, Tyger' group are working together to take down Red John themselves. They are using their professional positions to find Red John with no care for how they do it. I do not believe they are working FOR Red John, I believe they are working AGAINST Red John.  After Kirkland revealing to Jane why he was after Red John, and that he would stop at nothing to catch him, the 'Tyger, Tyger' group decided to put him down. This also leads to the Red John suspect list moving down to 5.  

The 'Tyger, Tyger' group know Jane is the only way they will catch Red John, which is why they've not killed him. The Private Investigator who bugged the CBI office was not in fact working for Red John, but when she was visited by her killer, she recognised him as the man who paid her to bug the CBI office. This was the 'Tyger, Tyger' group. Knowing that Patrick will never willingly tell anyone else anything about the Red John case, the group decide to bug his team to listen for any further developments.  Once Jane realised the office is bugged, the P.I. must be removed or she can identify to Patrick who it was who hired her.  It's worth remembering that upon finding the P.I., Patrick asks her 'who did this?', assuming it was Red John. She then tells him about the dots on the arm, which unwittingly puts Patrick on to the trail of the 'Tyger, Tyger' group.

While finally getting together the 5 final suspects, Patrick finds that 3 of them had the dots, thus connecting them. Here he will find out about the group, and realise none of them are Red John, although they have become murderers and criminals in their hunt for him.

In a nutshell.....

Partridge faked his death. He is alive, and he IS Red John. 'Brett Partridge' may not even be his real name, but he is Red John. He plants explosives at Jane's house in order to finally stop Jane and also remove the 5 suspects. With them all gone, Partridge would be free to kill again as often as he wanted, with no chance of being found out (as he's presumed dead).

Let's see how it all plays out.....