I think that Red John is Gale Bertram because:


-He drinks tea(3x24)
-He quotes part of the William Blake poem(3x16)
-He helps to frame Hightower when he informs La Roche that Hightower had a relationship with one of Todd Johnson's victims which shown she had motive
-If the 666 theory is right then it links to Bertram.
-He is quite powerful because he is the CBI director
-When he first meets Jane he calls him boy wonder which is what Jane's father called him and not many people know that.
-Jane said Red John would be at the mall on the season 3 finale and because Red John wasn't Timothy Carter, it only leaves Gal Bertram.
-When Reede Smith, McAllister and Bertram are talking it appears that Bertram is leading them some how and we now know that they are in the tyger tyger group and we know Red John is likely the leader.
-Bertram led Jane to O'Laughlin by mentioning Rope and O'Laughlin led Jane to Timothy Carter who Jane killed and went to prison for it.All caused by Bertram and to do that he had to know that Jane was setting a trap for the CBI mole because O'Laughlin told RJ and if RJ is Bertram thats how he would have found out.
-When Jane invited everyone to his house Bertram was one of the people who was sat calm which is how Sophie Miller described Red John.
-If Red John killer the PI then Bertram is easily the strongest suspect with only McAllister and Reede Smith left
-It's not much but from the last time I looked at the cast in the episode "Red John" Bertram and Smith were the only two suspects there and I am pretty sure its not Reede Smith.