I think its Bret Stiles. He is The one that would enjoy Jane Boeing tortured as well as leasing him in The dark, pulling strings for The search. He is a psycic like Jane and he us The one that can read him better than anyone else. Kristina Frye was also an psycic and she us friend with Red John hence Bret Stiles.
Bret also likes to control people and that is also what Red John likes...controlling people to do what he wants them to Do like puppets or marionettes.