Fisrt of all I want to ask many of you to stop thinking that Brett Partridge can be RJ! Why? Because he is dead. How can you think PJ and the CBI would have made such a mistake by having not deeply checking this little detail?!? In my mind he was obviously the first victim because most of the fans thought he was RJ (CSI and DEXTER influence? Maybe!). RJ killed him because he was irritated by the fans as he was by PJ in the past!
6 left.

Bob Kirkland is dead!
5 left.

Bertram, Smith, McAllister, are connected by their tatto to what we supposed to be a secret organization. This tatto is also something PJ would have noticed for long time if all RJ "tools" had it (mostly Lorelei). We already had a clue about this connection in episod s6ep02 when Jane surprised the 3 of them during a secret meeting in Bertram's office.
2 left.

Except is age, Stiles is the perfect RJ, powerful, clever, with influence on many people,but he is too old to be RJ. I think he knows who RJ is and try to protect him because he has a sort connection with him. Of course we knows RJ was/visualize but it's possible that Stiles is RJ's father or at least family member. Or just becuase RJ is Visualize member, he considers him as his one of his child.

RAY HAFFNER is my RED JOHN.
perfect profile. Member of Visualize. He was CBI before leaving to found his own company. Maybe he realized PJ was about to find him and he prefered to distance himself. We also know he has fellings for Lisbon, this might be the reason why he did not kill her. He also knows very well the team, so he can anticipate their moves.
Remember Lorelei told RJ and PJ were the same. both of same got the same charm and elegancy and should seduce the same kind of girls (Lorelei, Lisbon, Frey).

This is my theory, now let's wait and see!!!