I think that Pete having the outfit is justa red herring and he isnt the killer, it would be too obvious. But I defiently suspect Gigi, she distracted Grace's father and she seemed suspcious when he was outside. Obviously, Boone is an acomplice as we now know, so he must have a motive right? I think that there's a huge chance that the Red Devil is that girl who died's kid but maybe its not and that was just to lead us on.
I read some reviews sayingg that the episode sucked, but I LOVED it!