Not an theory but just information.

Did anyone else notice in the last episode 6x06, when patrick was sending the message to the suspects mccalister had an wedding ring on his left hand. Just like bertram has. I dont know if he is red john, but it was kinda weird he didnt had it when they were at patricks house.

Also i noticed that rj is left handed but is killing his victims with his right. He also shoots with his right. two suspects are lefty. one is haffner and the other is mccalister.

I still think that haffner is rj, but mccalister, partridge and kirkland would also be a great rj.