Bertram Said to Jane : I need to be on the boat when you catch that fish ...(in saison 5 we know that there is maybe a link with fish with Jason Lennon)
                                 I am many things to many people...(redjohn friends and what they see on redjohn, he help them...)

and in the final of the episode 1 saison 6, we can see in the GPS that P  = Partridge and B = Bertram ... S1 = Stiles S2 = Smith H = haffner K = Kirkland M = McAllister and Bertram is not so far than Partridge on the map...maybe he is RedJohn

what do you think ;) 

The original Red John was Partridge, of course; after season II, Bruno Heller abandoned that idea and there has been no John for quite a while (probably all the way to season V), until he finally found his candidate - someone more powerful and interesting than little old Brett was.
As to who the new John is, well... either McAllister (just because that choice would be among those unexpected), or (logically) Gale Bertram.
Note that when the seven supposed suspects were only shown in silhouettes, one - and only one - was portrayed with a prominently *blue* background. Well, consider that blue and red are the ends of the same spectrum...
(Amusingly enough, Bertram has recently said - openly - "I am MANY..." in an episode. ;)
By the way, you can vote for essentially any Red John candidate here: http://poll.pollcode.com/76818_result?v

Like "The Tyger" poem by William Blake, this one caught my attention to..

The Wild Flower's Song

As I wandered the forest,
The green leaves among,
I heard a Wild Flower
Singing a song.

'I slept in the earth
In the silent night,
I murmured my fears
And I felt delight.

'In the morning I went
As rosy as morn,
To seek for new joy;
But oh! met with scorn.'

I don't know who's my suspect now, but I'll still bet on Bertram as RJ & Van Pelt as his accomplice because RJ needs someone in Jane's team to be his eyes & ears.
And I believe that the poem The Tyger is not the only hint written by William Blake, perhaps clues can be found in several of his writings.

Hey Guys I've been watching the mentalist since S01E01. Believe me guys Bret Partrige is in fact dead it has been confirmed by Bruno Heller and CBS so please for you guys who keep saying he's alive it's not true. As for who red john is I have been suspecting Bertram for a while now and I just landed on Michael Gaston's profile on twitter (he plays Bertram). I found an interesting picture which he posted in August along with another one. He was shooting for the mentalist S06. It says: ''NO QUESTIONS'' on both the pictures.

Here is one of them... https://twitter.com/Gastonacts/status/365294786237841410/photo/1
Although it surely does not mean anything I feel like a ''bloody'' Bertram could be quite suspicious given that he is the CBI chief. Regardless, it's not hard evidence but I am really starting to believe it's him.

If you pay attention, there is no interaction between Jane and Red John at the phone call. So I guess RJ made Patridge record this message and used it to misslead PJ.

Btw

For fun..

1) Newbie Killer Level = Patridge isn't RJ, the real RJ killed him....
2) Serial Killer Level = Patridge is RJ, he fakes his death...
3) Master Mind Level = Patridge isn't RJ, the real RJ killed him and will hide the body, so everyone will start thinging Patridge faked his death (2) and will blame him for being RJ...
4) Red John Level = Something else, because all that sh.i.t is previsible and RJ isn't.

Look at the promo video of Season 6, on this link :
http://www.melty.fr/the-mentalist-saison-6-mariage-en-vue-et-nouvelle-video-promo-video-a212804.html

Now, stop the video at precisely 00:20 ! You will see Lisbon and Jane standing in the bureau of the CBI, with a smiley on the window and one on the floor, and two corpses : the ones of Grace and Rigsby ! What sentence is written in red ? "Behind the Smiley"
Later in the video (at 00:25), we can hear the voice of Jane saying loudly "LISBON !", and her being surprised. What can you see behind her ? The one smiley on the window that was before in the scene with the two dead bodies !

Now, what can we suppose ?
First : Both Lisbon and Jane discovered the two dead bodies of their team in the night (the flashlight of Lisbon), Grace and Rigsby were dead a few minutes ago.

Secondly and THE MOST IMPORTANT ONE : Red John didn't fear coming to the CBI at night to kill two experimented agents in the same place. That means :
- He knew he wouldn't be suspected if he were found in the CBI before escaping. It IS someone that can regularly move in the CBI ;
- He knew he would be able to kill them both before they could react with their guns. Grace and Rigsby didn't have the time to react when Red John killed the first one of the two. It must be someone they knew from the CBI, not someone like Sheriff McAllister who would be directly suspected if seen in the middle of the night in the office.

OR : Red John managed to hypnotize and kill them with them reacting. We know Grace likes Bret Stiles's speech, can't resist to his words. He could have easily hypnotized her, then kill Rigsby right after that.

Who could be seen in the CBI late in the night without being suspected ? Only Gale Bertram could.

So, I'm left with only two suspects if Bruno Heller wants to make things coherent :
- Gale Betram, being logically there because he's the head of the CBI ;
- Bret Stiles, possibly because he would easily hypnotize them and is the only person we know that can be anywhere with some excuse.

I just put Gale Bertram because I can't choose the two, but I'm still thinking about it. I have looked for tips in the 6x01 end for both of them. Have reaaally interesting things, but can't decide whether it makes sure it is one or the other.

I'll quote one sentence of a pretty clever guy we all know : "I'm getting close, I'm getting really close ..." And you ?

Bruno Heller said the clue was "buried" and fans wouldn't understand it until later on down the line. Therefore, I'm not going to bother thinking about it because bit wouldn't be anything we expect anyway. Just a thought...