My gut feeling, even before seeing season 5, was Bob Kirkland. After seeing season 5, he became a little more obvious, so I started second guessing my "gut feeling," but still cannot dismiss him.
Some thoughts:
*Most people refer to Patrick Jane as "Jane;" however, there are 3 people that call him Patrick: Red John, Bob Kirkland, and Bret Stiles.
*Bob Kirkland not only proves that he is a cold/calculating killer when he kills the man that can reveal who RJ is, but also exhibits psychopathic qualities as well: he is very calm ... says if he were in this situation he would want a "friend" to do this for him (people are always referred to as being "friends" of RJ).
I'm not 100% sure, of course, but Bob Kirkland was definitely my original choice. The only thing that I am struggling with in the theory is that Visualize definitely seems to be at the root of everything ... between the red barn smiley face, Lorilei saying that she has reached her full "reality," after the death of her sister (that nothing can hurt her now), and the extreme "cult" following / almost hypnotic devotion of the group.
