1) For the Partridge friends -- It can't be him because he's wrapped in plastic.  I think Cho would have noticed if it wasn't Partridge.

2) Bertram is a bad man, but I don't think he's RJ although he is my obvious #2 suspect.

3) The shots we see of RJ in this episode look more like McAlister.

4) As I've said for a few weeks, McAllister is the only character with a listed age for his character that doesn't just assume the age of the actor playing him.

5) He's been there from the start.

Arguments for Bertram -- he was there in the mall with Jane (we were told we would see RJ), but we were also told we would catch a glimpse of RJ and that seemed like more than a glimpse.

6) Bertram doesn't seem crafty enough to be RJ where as the Sheriff does seem crafty enough.