So folks, my brand new theory.

I hope you won't be disappointed because I am not telling you who Red John is, but just eliminating.

From list of 7 suspects, I truely believe that I can eliminate two of them at this moment. I truely think that Gale B. and Reed S. are not Red John. Why?

S01e23, Rosalind Harker said that Red John is 'just under 6 feet tall'(180 cm) and both of them are 191 cm tall. She couldn't miss by that much. Gale could also be eliminated because he seems a little to stupid to be Red John. He can't even win a poker game without Jane's help.

So that was what I think 100% is true. Heller said that Red John will be relieved by the end of the year so ii suspect that every episode will mean elimination of one suspect. So McAllister could be eliminated in second episode of 6th season. Bret S., who is only one powerful enough to be Red John, is a little to old to be someone's lover and stay in bad for 2 days. Don't you think so? so Ray, Brett or Bob? Instinct told me Brett, but mind said Ray. He is connected to Visualize, he has money and time. Red, Roy, Ray...