I still think it could be anyone, but one thing I think warrants focusing on is the scene where PJ sets up the two guns. It's very deliberate. In screenwriting you don't waste screentime on anything not really relevant. I think it is the pistol he wants to kill RJ with not the shotgun. Also the placement of two guns makes me think that he des not know who RJ is but he atleast knows of 1,2,or 3 that are definitely not RJ. I think he discovered that a while ago over the past three episodes and ever since making his list. He is too smart to not have atleast eliminated one or more suspects from his list. If this is true, I think atleast one of the 7 is aware, from Patrick, of atleast part of a plan that PJ has. I think this also may involve one or more of them being fake-killed. Maybe Stiles knows (since hes the one PJ had to go and see). Maybe McAllister is an ally and played the plan well by saying "it's not what you think." I think that nothing in the promos is as what it seems.

Questions for those who have more attention than me. Where do we see the photoboard with dead suspects that everyone is alluding too. I can't find that...