Even though Red John is dead, his disciples and the Blake Association are still out there. Will we hear from them again?
Heller: I never say never, but I would say I think the audience and the story demands that we step away from that trope for a while. The trouble with these sorts of stories where you're playing tricks on the audience, with who-is-it mysteries, is you can get way too mysterious. There are people who said all the way along that Patrick Jane is Red John. When you've got that kind of elaborate thinking out there, it's dangerous to come back to that story unless you're coming back full force, because then maybe will start thinking, "Oh, maybe Red John's not dead." Red John is dead.
http://blog.zap2it.com/frominsidethebox/2013/11/the-mentalist-after-red-john-then-what-simon-baker-c...