There's no way that Pete is the actual killer, but i can say that he is being played. When he was on the phone call with "who ever" he was trying to warn him/her that they need to leave town. Now that stating that it's actually 3 RD's. I think that it may be Chad. In the episode where all the Dickied were out, and it revealed the two killers. I'm guessing at that time Pete was one of them, while he was covering for Chad. Chad may just wanted a show or to show that he isn't the killer. Also, in the Black Friday when Chad approached Pete. I think the reall reason why Pete did "those things" with Boone was because Boone might wanted to snitch on him about something. Chad told him that he would be a dead man. And that's what happened later one, when he called Pete. Chad slept with everybody, and he killed the ones he didn't "you know". He tried to kill Dean, because at the beginning of the show they were both lying in bed together. Chad told her that he loves her, but she turn him down.
Also, my other thought is that Pete maybe the one to turn the deep fryer on. Who else would be around in a coffee store to hear her and her maid conversation. He was right there. He knew that would crush Chanel, and to let people think she is a killer.