Red John is Patrick Jane. Think of the episode where Luther Wainwright did a psychopathy test on Patrick Jane and according the score Jane was considered a Clinical Psychopath. That was put on the show for a reason and we all know what happened to Wainwright on the last episode of season 4. Also if you remember the episode to where Bret Stiles meant up with Jane and gave him the note that lead to Kristina Fryes location and Patrick Jane asked Bret how he knew about Red John and Bret would not give Jane an answer. This is because Bret has Jane somehow figured out and Jane knows this, but the only thing keeping Bret safe from Red John is his status and willingness to say nothing else about it. I think Jane knows deep inside that he is a psychopath and has multi personality disorder and to convince himself he's not he will stop at nothing to hunt for Red John to later find out its been him all along.
