Bob Kirkland from Homeland security.  Watch season 5 episode 7.

 I'm glad i found this site and the fans on here that i can chat with about the show. It's one of my favorite shows. House(rip) Breaking Bad, Person of Interest, Justified. The Walking Dead, Dexter, Homeland, The Mentalist, Elementary, Monk(rip)Psych, and Seinfeld reruns are classic and never get old.  

Also, If you enjoy The Mentalist, Then you'd enjoy White Collar.

If you guys don't mind, i would like to submit my opinion. I have no theory about who red john is. But i have a few comments based on simple deduction i have deduced during the series.
   
 Bret Stiles, J.J. Laroche, Gale Bertram, and Walter Mashburn (no particular order) are all decently plausible suspects.  I'll throw in Susan Darcy just so my list won't seem sexist. 


 Grace Van Pelt, Oscar Ardiles, Wayne Rigsby, Summer Edgecomb, Lorelei Martins, and Harker Rosalind are all too young to be red john

 i consider Minelli, Lisbon, Hightower, Cho, and Frye as friends of Jane, So i doubt it's any of them.

Stiener, Wainright, O'Laughlin, and Bosco are all dead, So it's not them. they are dead with witnesses to their respective deaths

There are many people who kill others without so much as an expression
on their face.They don't feel excited when they're doing it, they are
perfectly calm and if you check their pulse, it's normal during the act
of murdering another being.Those kinds of people don't really kill for
hedonistic reasons, they either kill for money(as in being a hitman or
inheriting a fortune), for prestige(something that has to do with how
proud they are, feeling of control and power) or for a mission(that is
to say they believe they achieve something by doing the deed, like
ridding the world of evil men or saving it).As humans, they are all
unstable persons, but as killers, they are not unstable because they
don't have an urge to kill like a sadistic killer who does it because he
gets off of it.Because they can actually stop, after they have enough
money, status or accomplishing their mission and they don't kill
spontaneously.But a pleasure oriented killer never stops because he
revels in it.And there are more types of hedonistic ones, like the
fantasy fulfilling ones, revengeful ones(targets a specific type of
people like only men, women, prostitutes, rich people) and so on and so
forth.
If you ask me, Brett clearly seems the type that is pleasure
oriented(that is if he is a serial killer) while Red John seems like the
mission oriented serial killer(the higher path, nobler existence, he
has a mission of love-Rebecca's words) and also the one that is looking
for prestige(killing Jane family to show Jane he's wrong and give him
power over him, killing everyone that insults him like that interviewer
who called him "beast" and James Panzer who brag that he surpassed Red
John's status as a serial killer).
But here's the thing, Red John's
profile obviously changed since the first season.At the end of the first
season, he seemed to be the pleasure oriented type, actually he clearly
was meant to be like that.Killing only women(revengeful type), cutting
them with a knife(indicating that it is something personal like he felt
he was betrayed by women or he was really traumatised by one when he was
young, maybe she raped him or killed his family), entering their rooms
at night, waking them to see the fear in their eyes, cutting them and
waiting for them to bleed out(the fantasy fulfilling type).As we can
observe, he was clearly meant to be a hedonistic(pleasure oriented)
serial killer in the first season, the only person he kills that doesn't
match his profile is Jared Renfrew, which was basically forced to do it
since Jared pose a threat to him having info about him.Then in the
second season, Red John changes a lot, he gets an upgrade, he has
disciples willing to do anything for him(even die), he is an educated
person(reciting Blake's poem) and he's resourceful.The more we find out
about him, the more complex he becomes, his profile is changing and he
doesn't even match his serial killer persona because serial killers
don't have followers, at least not usually, he matches more the con man
with his own cult like L. Ron Hubbard which is why it was obvious for me
that sooner or later it will be revealed he has some ties with
Visualize, since Visualize is cult just like scientology, actually
Visualize seems to be a parody of scientology.
This is why Brett
Partridge can't be Red John, he was a perfect candidate in the first
season(he was my first suspect and the obvious culprit in the first
season, no one else could be Red John in the first season) when Red
John's profile was that of a hedonistic serial killer, but then Heller
changed Red John a lot for the plot sake.That's because the first season
is just like the pilot episode, if it's good, your series gets renewed
for a second season, if not it gets canceled.That's why they make two
season finale, one that opens the road for a second season(if the series
is renewed) and one that ends the series at the end of the first
season(in case they don't get the approval for continuing the
series).Since Heller couldn't know if his series will have a second
season, he made a few Red John centric episodes and in the finale, he
had Patrick getting close to Red John.That formula was used in every
season from 1 to 4, because Heller was in the same situation, not
knowing if the series gets a new season, he had to be ready to end it at
that season.But now it's different because Heller has confirmation that
his series will have 7 seasons(or at least 6 seasons) so he knows he
doesn't have to end it this season in case it gets canceled.That's why
we get more info about Red John in almost every episode, little by
little we get there.

This Theory covers the Red Moon episode mostly, but also has more things in general. Also, I prove that Brett Partridge is not Red John (in the end of theory). But before that, my humble opinions about the series:

I started to hate coming up with theories. The reason is that for almost every single character in the series, we can come up with a solid theory, and it can be true when RJ's identity is revealed. I read somewhere that Bruno said that a good observer can find Red John. Well, we observer everyone and find that everyone can be Red John. To make sure that we would never be %100 confident about who RJ is, they added so many fake clues that it started to be disgusting. Now, everyone is a possible RJ, and everyone is a possible friend of RJ. 


Turning to analysis

Let me start with general information. Patrick Jane has never ever been a step ahead of Red John during the series. Only when he was acting down for  6 months, but Red John learned Rigsby was not dead and he was ahead again.

Red John knows that Patrick solves cases by setting traps for suspects.

If we assume that Ellis Mars is Red John

In this episode, Ellis Mars patiently waits for the person in charge. He wouldn't talk to Van Pelt, waits for Lisbon. But actually he was waiting for Patrick Jane, because he knew Lisbon wouldn't be interested in his psychic crap and he would be able to speak to PJ.

He says: The killer is to strike again.

The killer does.

Later Mars tells Lisbon that she was the last person to speak to murdered sheriff Mullay.

Also correct.

How can he know these? He has to know that killer is Todd, and he must also have been talking to him. Mars was not the actor of the play, so he can be the director or scriptwriter. 

In the hotel room, Todd can't kill Mars. He is in trap, and he tries to shoot PJ with the gun. When pulling the trigger, he says The big picture would blow your mind. He fails, is taken into custody he wants to talk to Jane, saying that They have something in common. 

And when he is dying in hospital room, he says: Tyger Tyger
-------------------------------------

Now, as I said, Patrick Jane was never ahead of Red John. Everything went according to RJ's plan.

In the hotel room, Todd doesn't kill Mars. Why? I will explain in a second. But before that, he tries to kill PJ. Why did he pull the trigger? Because he knew the gun wouldn't fire. They would never kill Jane. RJ knows that PJ always uses traps to catch suspects, and he knows that PJ would never use a gun that works. It is loaded because Todd would be able to distinguish the weight between a loaded and unloaded gun, or he might wanna check the bullets. So, there is no firing pin. He draws his knife, and PJ calls Cho and Rigsby.

When Cho and Rigsby come, there is a smile on Todd's face. Everything is going according to plan. 

Now, why didn't he kill Mars? Since this episode is a work of Red John, everything must be arranged before. If there was no Ellis Mars, there would be no trap. So, Mars is an essential part of the plan. Mars is not a random guy. There is no way he would know those things.

Either:
1) Mars is Red John's friend, who is playing his part in the game.
2) Mars himself is Red John. 

Todd knew he wouldn't be able to kill Mars even if he pulled the trigger, as he knows gun won't fire. His part there was to be caught in trap. He acted like he couldn't shoot.

But, someone sets him on fire in CBI ( probably by Craig O'Laughlin, though never evidenced as far as I know ). Now, when he opens his eyes in hospital, he says, tyger tyger. What the hell? 

If you are betrayed, and tried to kill by a horrible thing like being set on fire, the first thing you would say is the name of Red John. But instead, he says tyger tyger. This can only mean one thing. He knew that would happen. 

So what crazy mind accepts being set on fire and killed? Answer is all actors of Red John. Rebecca was smiling when she was killed. The assassin going to hotel room to kill Hightower died gladly by jumping. The guy keeping the girl in the house also died without telling anything. This could be a thing about the higher path Red John was talking about in season 4 finale.

I strongly believe that the episode Red Moon was for Todd. He played his part for the higher path and died. It was Red John's gift to Todd.

Another thing about this episode, Todd says, the big picture would blow Patrick Jane's mind. He is not saying that identity of RJ would blow his mind, but the big picture. So, RJ can still be a side actor, but not Ellis Mars. The thing to blow Patrick's mind would be the game played in this episode. 

Lastly, the building used in last episode of season 2 where Jane and RJ met is the same as the building for sheriff in this episode.
http://i46.tinypic.com/w02r2p.jpg
http://i45.tinypic.com/w9a88o.jpg

Interesting? Yes. This could be a hint to us, or maybe they ran out of buildings.

Now, as promised, I will stop talking about Red Moon and prove that Brett Partridge is not Red John.

How do I know? In season 2 finale, you remember the fake Red Johns killing some girl. The couple in film club at college. At that episode, PJ goes to house of the murdered girl and starts looking around. Brett Partridge is also there. He is saying things like hurry up we real guys should find actual evidence. Patrick Jane says some things to him, irrelevant to my proof, and goes out of the room.

When Patrick is out of room, Brett says: JERK ( Season 2 Finale, Time: 11:06)

This is the proof that he is not Red John. He is just an amused scientist. Why? Because when he says JERK, there is no one in the room, only Brett. Nobody can hear him. And Red John would never call Jane jerk. Red John likes playing games with Patrick, and he possibly admires his success in cases. A smile, it would be what RJ would do, but calling him jerk? Never.

I think that Red John COULD be DANNY RUSKIN:

I am watching the whole program again from start to finish and just watched S3E2, Cackle Bladder Blood. It seems that Danny Ruskin, Jane's estranged Brother in law fits very well with the physical description that we have of Red John by this point in the plot, and also the soft/high pitched Red John voice that is now quite familiar to us. 

People could say that it is unlikely he would have wanted to kill his sister and niece but he was after all seen to be annoyed with her and Patrick for leaving the carnival life- this is not something done lightly.

In this episode S3E2 Jane calls Danny a 'sociopath. like all good con men', and he has also referred to RJ as a sociopath.

I think it is interesting that Danny is introduced to us at this point, just after the 'Tyger Tyger' episode at the end of season 2 and us actually hearing RJ's voice for the first time etc etc.

Finally the meaning of the name 'Ruskin' is 'red haired' like the name 'Roy', a known one of RJ's pseudonyms.

Ps. I hope when Jane finally gets closure him and Lisbon get together, and Rigsby and Van Pelt should get back together for the ending too!!

Tolman Bunting is a character who appeared in 18-5-4 (the mentalist 02x21). He was very good at chess, able to keep Jane occupied for several days. He worked as a professional codebreaker so i think he is on the same intelectual level with Jane.
My theory is supported by the fact, among other things, that he shook hands with Jane. He is a man who has both the means and his ability to hack into any system (whether he was able to fix universal decryption device or not) and he knew Janes story. Tolman Bunting has a face of a mad genius. Maybe I'm wrong, but I think his profile corresponds to Red Johns.
I'm not quite sure but I think he had the same dubbing as Red John in the last part of 2nd series. It is not much, i know... but red johns profile has only two people... Styles and my suspect.

this people is good in their work 
no one suspects .... Picardo!!!!
i mean Jason Cooper

the real reason is that he is the only actor in the show who has what it takes to pull a satisfactory red john.
i´m not his bigger fan but by far he is the best actor in the show. period. that´s enough.

why is Jason Cooper?
red john,... just remember what Patrick said about him since the beginning:
e01s01 patrick answer the questions in the tv show
he tells that thanks to spiritual contact with red john he can make a profile of him
well, we know it´s not a spiritual thing, it´s pure skill
but he needs to make a living so he has this explanation 
but the profile it´s as good as it gets
he is at the peek of his abilities, he can nail it with his eyes closed
red john is a sad ugly guy
that´s all we need

red john is just like as clever as patrick but is not patrick
beside smarts you need the ability to connect with people
you need the personal attractive
red john can reach isolate persons but he has not what it takes to reach people

we know he is in visualize 
right
in the second row
planning to take over but unable to do what patrick or stiles can
unable to lead
he only can pervert
he sure has an interesting relation with stiles
one that include blackmail and worst things

the thing is: 
we know who red john is
please, reveal him in the last episode of this season 
and make next season a killer with patrick not knowing who he is till....