In S05E08, Red Sails In The Sunset, we see Bob Kirkland make a phone call while (from memory) he is standing in Lisbon's office. He is calling with a person called Tom and the call is about getting the Marshalls involved into the case at hand.

Remember Jared Renfrew? In S01E11, Red John's Friends, the clue left for Jane by Jared Renfrew, written in blood on the bathroom wall, is: 'He Is Mar'. Main theory on this clue is that Renfrew was trying to write 'He Is Marshall' but that he succumbed to his wounds while writing the message.

I believe that this call between Kirkland and "Tom" is the follow-up to this hint. Kirkland is actually calling Sheriff Thomas McAllister (who goes by the nickname Tom), and that this was one of the direct hints dropped in Season 5 (which went quite overlooked as I can't find anything on it) about Red John's identity. One of the earliest hints that Red John is in fact Thomas McAllister.

(I've rewatched all of the Mentalist episodes in the past few weeks and this was one of the bigger things I've noticed) 

Great series, but the last seasons were awful. FBI? Can't suspend disbelief on that.
If I were to pick a number one Red John candidate, then it would have to be Rigsby. His father was a biker dirt bag, he fell in love with the redhead, he says things that are out of character, and he is, like someone else said, a classically trained actor. There could be no better choice! 
If one were to watch the episode where he is on an island with the cbi team solving a murder, then one could see how Rigsby could be a great Red John. 

Well ... it really was the sheriff ... But... Am i the only one who thinks that it doesn't make any sense?
I continued to watch the show until it's end but i honestly think everyone in this ("who is red john?") comunity put more thought into the whole red john thing than the writers of Mentalist.

There were too many things left to explain, too many things didn't make any sense and... lets be honest... There were several candidates more probable than the sheriff ... Stiles, Kirkland, Partridge, Bertram, Brenda, Royston Daniels, Mashburn, Rosalind, Van Pelt, Lisbon, Volker,  Minelli...
All of these had reasons to be suspects and, at least, half of them were better candidates than the sheriff...

Do you agree? what are the things you think were left to explain? What was the better candidate?
Any theories that make more sense than this "sheriff" conclusion?

https://www.youtube.com/watch?v=tZhuRb-kcGM  The best Scene for me :(