I've long suspected Haffner since the beginning, and many clues people here have pointed out, like him being the only suspect to call Teresa by her first name (a la RJ), or the fact that he uses his left hand like RJ, only add fuel to the fire.

One interesting thing I noticed when I rewatched the last episode Fire and Brimstone occured during the tattoo reveal scene. I noticed that when Haffner pulls down his shirt to expose his left shoulder, he does something inadvertently and/or sunbconsciously. The camera pans to him, and he doesn't just expose his shoulder like the other suspects. And he just doesn't point it out. He actually shows his shoulder, then runs his fingers in a horizontal direction, from the back of his body towards his front, where the tattoo would have been. You'll also notice that this direction corresponds to the decreasing sizes of the three dots.  It's almost like saying "see, I don't have it." He did this without seeing if anyone else had the tattoo, or even knowing what it looked like.

This is something that RJ could easily have covered, if he does in fact have it at all.

Another possible scenario is that RJ has a different tattoo at the same location as the Tyger, Tyger people, and this tattoo means that he is the boss/leader of the organization.

Still think Partridge is Red John??? Take a look at the comments!!!

Jane, Cho, Rigsby or anyone else other than the five suspects left on the list is NOT going to be Red John.  Heller has already stated in interviews that it IS indeed one of Patrick's five suspects.  He also said he believes we as an audience will be disappointed when we find out who it is.... This makes me believe that RJ will be Bertram.  I just think thats he has been kind of the, "thats way to obvious" suspect and therefore we wouldn't assume it would be him.  If not Bertram, I think that RJ is going to turn out to be Haffner. I believe that the tattoos are marks of the Tyger Tyger members and not necessarily a mark on the real RJs arm.  RJ has always been a proficient killer who has planned his killings out meticulously and with good timing.  Not to mention, he for the most part, has ALWAYS been one step ahead of Jane.  I think RJ sent someone to kill Tinsley, because it was a sloppy, rushed murder without the notorious bloody smiley face like usual.  Also, when we supposedly saw RJ back in season 2 wearing a mask, he was very slender.  Haffner is definitely  my number one suspect.

I noticed one thing when Stiles arrives to Jane's house. First he take a look inside, he notice that nobody is their. Then he says "Am I early?". This means he knows he's not the only one invited. How? I dont know, he might have talked to Haffner before but who knows, he maybe talked to Patridge (maybe his son?) that got it from Bertram. Im very excited to the "Red John" episode.

When you press Green or Red on my theory, remember it's not a theory that Patridge is alive, I think he's dead, i was just making up possibilities.

I most say that i never been this excited about a "series final" ever :D 

I’ve found
some clues that point directly towards Haffner as RJ in past seasons, and also
in this sixth season he gives away some small things (not the spider, that’s
just a silly clue).

 




First I
will summon the most important parts of his first two appearances:

 



                                                  S04E02 Little Red Book          

 



-> The
fake Red John was killed by Jane according to plan, the real one is in the clear now and finally risks
to step out of the dark to meet his antagonist.

  



-> At
the beginning Lisbon tells Jane that Haffner was FBI and very good at
wiretapping & surveillance. Later on, Lisbon is home alone and decides to
investigate the Timothy Carter case a little further. She wants to know whether he was RJ or
not. She calls LaRoche and asks him if she can visit the widow, Sally Carter –
she’s in jail.

 



Next scene:
Haffner is in a panicked hurry and tells Van Pelt (who was reporting about a
case-development) he’s busy. Not very professional of him and it clearly has a
reason. He probably wiretapped LaRoches phone and knows what Lisbon is planning.

 



When Lisbon
arrives at miss Carter’s cell she’s dead (fake suicide & fake letter that
acknowledges Timothy Carter as the real RJ).

 



-> I
also believe in the Heisman clue, which I read about on this magnificent website.
Plus Haffner is lefthanded.

 

 




                                               S05E13 The Red Barn

 



->
Haffner asks Lisbon to join his private project. Though the really important
question for him is how much the CBI knows about the Red Barn murders from 1988.
By asking about the names on Cooper’s archive-list he gives himself away. First
he looks relieved when it turns out his name isn’t mentioned in Cooper's info. But it was
impossible for him to know about this information, unless he’s Visualize
himself, a connection Lisbon easily makes. Haffner talks himself out of it as
best as he can.

 



This must
be a VERY loose end from 1988 when RJ was still young and careless, because Ray returns at the end and is upset the mother and
daughter will only go down for one Red Barn murder, instead of all three. Haffner
claims he speaks for his Visualize-clients, not for himself. Lisbon gets even
more suspicious. Ray, were you there? – Why would you ask me
that? We’re still friends, right?  Lisbon apparently forgets to tell Jane about this. 

 

 




Haffner
returns in the current season. Not in the first episode, but Lisbon & Van
Pelt put GPS trackers on the suspect’s cellphones, which is his MO (remember
the wiretapping). Easy for him to use it against them.

 



                                       S06E02 Blackwinged Redbird



->
Lisbon’s dream. Her subconscious tells her something. Haffner betrays her and
attacks her. For Teresa he has always been the most likely RJ suspect (she
clearly has a better intuition then Rigsby and Cho, who are both betting on
Bertram).

When she
wakes up from her horrible nightmare, Jane calms her. A nurse passes by and
asks for Carmen Lee. This looks like an indirect way for Haffner to check if
Lisbon is all alone.

 



-> A
little while later he walks in. Lisbon fears him, although he tries being
charming (other than most women Lisbon reacts in a distant way on male charms,
she does that with Patrick & Mashburn too – at least before she ends up in
bed with him). First he checks if she remembers anything. Then he asks about
Red John again. Why do you care? – I don’t
care. I have clients who care. The clients again. He doesn’t
like her questioning. Before leaving he states that someday he and Teresa will
have the time, as saying the last time (when he knocked her out on a creepy location) they didn’t
cause something came up.

 



-> RJ’s pseudonym
when visiting Sophie Miller was Jay Roth. I supect Haffner of having German
blood for historical reasons, so a possible connection. Although this isn’t a clue - just a personal
hunch.

 

 




                                              S06E05 The Red Tattoo

 



-> Strange
episode. Why would RJ use a spy, especially such a fudgy one, to bug the CBI? And
if Haffner is RJ, it wouldn’t make sense at all because he’s the master bugger.
So must be a trap.

 



->
Finally we see one of Haffner’s “clients” with our own eyes, and then that
client is simply Cooper, the errand-boy of Visualize. His contribution to the
whole case is pretty useless + he failed to protect the dead guy, who also was
a client of his. Two possibility’s: or he’s a useless cop (which would
contradict Bertram’s & Lisbon’s first opinion of him in season 4) or he ain’t focused
at all (which would mean he’s all about the RJ case again).

 



->
Haffner meets Jane in the elevator. When they leave, he tabs on Jane’s shoulder
and tells him there’s a comeuppance coming his way. Jane replies you’re even a worse psychic than you’re a
cop.

So if he
wanted to make Jane believe he’s a bad cop, it definitely worked. But indeed, this
is a silly prediction also by Haffner. Unless…

 



-> He
gets the autopsy-report of the stabbed man before Lisbon. He claims that he
still has friends in CBI, they help him if he needs it. Maybe Bertram is his “friend”,
since he also knows that Jane riled some very powerful people (later on he advices Teresa & Grace to step away from Jane's tricky business).

 



-> After
Jane solved the case, Lisbon asks Cooper where Haffner went. He had some business to attend to. I am not his only client. Haffners
vague client-alibi again.

 



-> …
unless he had it all carefully planned ahead. And he already has the gathering
of the 5 remaining suspects in mind. Would be a nice trick if he foresaw Jane
finding out about the spy being RJ’s, and very well timing to assault her just
before police arrives. Best part of the trick is to let her live for a few
moments and make sure she mentions the tattoo, which was easy to fake (I mean,
three simple dots?). Now Jane is unwittingly going after the Tiger Tiger clan
instead of him. RJ allready killed an important member of that clan in the person of Partridge, whose task it was to make some Tiger murders look like RJ killings, even maybe Lorelei's. It's possible he wanted to lure them Tigers out by taking away their forensics expert. 




 

 

                                             S06E06
Fire and Brimstone

 



-> For
the first time we hear Ray making a call with a real client, about a woman that
needs to be kept quiet. When he meets Teresa in a coffee bar, Lisbon can’t
help showing through she suspect Haffner as RJ. He now acts very well: not much
hesitation, just pretending angry and determined about it. You wanna question me you arrest me. An innocent man would, despite
of liking her very much, now detest Lisbon for good. But he kind of forgives her
immediately. And sticks with the plan. He wants to see how Jane will lay focus
on the wrong guys.

 



-> After
Jane tricked Lisbon and leaves her on the side of the road on his way to Malibu, the first car she
lifts for drives trough. It’s a Mercedes, and possibly the same Mercedes
Haffner drives. If it’s him, he off course will stop for no one, especially not
Lisbon, because at this point he cannot derive from the trap he (and not Jane)
set up. This is no real clue, more of a feeling it was him.

 



-> Once in
the house in Malibu RJ has to make one important move: make sure the Tigers get
rid of their guns. So he stands up (I don’t
have time for this crap) and forces Jane into taking the riffle and disarm the rest. Now his
real targets, the Tigers, are suddenly in a very vulnerable position. He is laughing at the inside, because Jane is dancing as his perfect puppet.
Maybe Jane has a counter-trick planned, we’ll that see in the next episode.

 

 




So, to
conclude: if Haffner will turn out NOT to be Red John, I’ve been misled very
well :) 
Though I can't help but imagine him sitting across Jane in a quiet place, saying oh, why do people always call me Red John
anyway? That’s just a stupid name, isn’t it?

         

In the season premier of the sixth season, at the end when Lisbon enters the house the door is closed in the room she finds Brett Partridge. She hears a sound and turns her back towards the door. The door is still closed. After she finds Brett Partridge and stands up, the door is open as she looks around meaning that Red John entered through that door.

This conclusively proves that Brett Partridge is not Red John.

Further, Ray Haffner is afraid of spiders and the doctor is convinced that Red John has some kind of phobia but it is not fear of heights. He is an excellent whistler. Also he is the only person who calls Lisbon by her name 'Teresa'. When PJ calls Lisbon's phone, RJ tells him that 'Teresa can't answer her phone.' He is directly connected to Visualize and is the right age to be Red John.

Ive been a frequent visitor to this site, especially over the last few months and its time for my prediction as Red John maybe revealed this weekend.
This is based off one of the 7 suspects in RJ.
After a lot of thought, I'm nowhere near 100% sure on this I'm going to have to settle on Ray Haffner.
A lot of the clues i can't seem to figure out, "He is ma (r/n)"
I feel, if anything the tattoo's rule Bertram, McAllister and Smith out.
I'll explain why him and why not the other suspects.

Reede Smith
Basically if it was him I'd cry. He hasn't been around long enough. He doesn't fit any of the RJ descriptions we've had over the years. (Not tall and this)
Also admits he's a lower level guy in Tyger Tyger.
Most obvious is that Lorelei Martins would go near him :)

Bret Stiles
Basically too old and doesn't fit descriptions. But I do think he's involved with RJ which I'll explain futher down.

Bob Kirkland
Only been around since season 5!!!!! He fits the physical descriptions we've had in the past, but I guess their can't only be 1 person matching RJ description from the 7. seen people say it's him or his twin borther. I think the twin brother was a legit reason he was hunting RJ. He asked the fake suspects (Thinking they were RJ) if they had seen him (twin brother) before.
Twin brother just another BS red herring from Heller i think.

Brett Partridge
I wouldn't mind at all if he turned out to be RJ. He's been around since the pilot and his first line ever was "Red John enters here". He's at every RJ crime scene and acts strange. The fact he's dead and it seems a little farfetched, even in this show, that he faked his death. He fits the description as good as anyone on the list honestly but surely way too young to have been at the Visualize Farm in 1988, couldn't be older than 10-15 back then surely.

Tom McAllister
He's been around since episode 2. Definitely creepy enough but just can't see him as RJ. Doesn't seem smart enough even if he is hiding it. He seems to like Jane too. Has the tattoo so a mid level tyger tyger guy i assume.

Gale Bertram

I think the tattoo rules him out and he's just a higher member of the Tyger, Tyger group. Doesn't fit descriptions as he's well over 6-foot and we've seen RJ from behind and he has hair. He's looked like a likely suspect for a few seasons now and can't see it being that obvious and surely Jane would have figured it out.

Ray Haffner
Okay, here's why i'm not 100% sure. He's only been on the show since the start of season 4. He's been accused multiple times of being RJ and reacted genuinely angry. He's been my top suspect since mid-season 5.

I think Ray Haffner is Red John. He's a member of visualize which explains why Bret Stiles has so much knowledge about Red John activities. As he's in visualize he could have been at the Ellison Farm in 1988 and would have been (as pointed out in the very same episode) 21 years old which fits the description that "a kid" painted the smiley face. He fits the recent descriptions, being tall and slim, not bad looking. He looked suspect as he was showing Jane if he had the tattoo. He acted angrily when Lisbon said he thought he could be Red John in last weeks episode instead of just saying no. This may have been done to rule him out as a suspect for Lisbon. He has a phobia of spiders which makes sense because in Sophie Millers notes she said he may have a phobia of something other than heights.

Summary
There's a few reasons why all these people shouldn't be Red John but Ray Haffner has the fewest I can find and has some good evidence supporting the fact he is.
If is someone not on the list eg. Walter Mashburn, Minelli or Ron lol I won't be too pleased unless they have the most complicated back-story of all time.

All I hope for is an epic reveal which links all clues we've got over the 6 seasons.