I'm starting to assume that the real RJ is really just Janes Father. Just think about it, he is the one who knows the way Jane think's the best, he knows so many stuff from his childhood like the last episode of season 5 shows, and he has not seen Jane for so long. Though my backfire is the "Shaking Hands" accusation Lorelei made when she spoke to Jane. Also if you think about it Jane's father must have hated him after he left him, so not only he killed his wife and daughter for revenge about all the trash talking he made about RJ (Jane did) but he took revenge because he abandoned him back in that time. Also he is age appropriate to be Red John.
Please let me know your thoughts since I've never seen such a theory.
