Killers motive?

I think we're supposed to believe that he always wanted to be with Sarah since she's the only one he knows who has experienced tragedy similar to his, the only one who could potentially understand him. He could also appear very heroic in this scenario. June is cheating on him so that amplifies it and Sarah coming back to town gets him going. Seven deadly sins in part inspired by biblical upbringing but more to confuse authorities about who the killer might be. It especially gives him cover for his other motive, to kill June and Trent. The Ariel angle gave him extra cover killing them. Still don't know why he didn't kill Dylan in there somewhere to make sure he'd be out of the way if this was his primary motive but, eh, whatever. I just love that he apparently had the ability to teleport a couple of times to get around the way he needed to. Horror suspension of time is the best.

Ah, well. It was dopey but entertaining.

He was a Psycho, killed his mother also. Doesn't need a motive.

Frankly it didn't need a final episode I would have been happy it it ended at episode 7. The last episode felt thrown in and really didn't accomplish anything