I think RJ is Robert Kirkland because firstly, when loraline is speaking about RJ to Patrick she says,"Its a wonder you didnt become best friends from the moment you shook hands."
Moreover there is a conversation between an FBI agent and Robert Kirkland. The FBI Agent  calls a man saying she wants to get rid of Patrick and then turns to Robert Kirkland saying,"Its done."
Last point: Robert Kirkland bumps into Patrick and then shakes his hand. Patrick says,"Do I know you?"
Robert Kirkland replies,"No, you dont know me, but I know you!"
 Go on youtube and type in Is Robert Kirkland Red John, Its the First option