I'm accusing a men from the last episode (S05 E07), Bob Kirkland from Homeland security. Maybe he's not Red John, but he must have some very strong relantioship with him. He came to agent Lisbon to tell her to get off from some powerful men called Volker who is also showed up in the same episode. Also, in his way out, he said hello to Jane but Jane didn't recognize him. Perhaps, Volker may have relantioship with Red John or he can be Red John. Director told there's gonna be progress with the Red John's case in the fifth season, and there it is. Now, we must wait 1 week to see how this case is going to develope. Can't wait!
