We got a clue in the latest episode with his feakout of seeing the spider on the wall.  Ive seen people that claim the dictation of Sophie Miller stated the patient suffered from a severe case of "acarophobia" and that jane quickly stated the fear of heights which lisbon replied i know.  The above mentioned phobia is the fear that the skin is infested with small crawling organisms.  This is incorrect.  Listen close and turn on CC if needed it clearly states "achrophobia"  the fear of heights.  This could be another red herring that Red John threw out to distract Jane.  Its obvious that the spider scene is significant, he is terrified of them.  There was a clue given that red john likes cold, insects dont like cold and he would be more comfortable in that environment.  The other thing is that in episode 6-1 Red John did not kill lisbon, because he likes her, he painted the face on her, and he referred to her as "Teresa" which almost everyone else refers to her as "Lisbon"

Haffner is Red John