The ONLY good part about the finale was that Deb caught him.
There was so much stupid shit in this episode. How convenient that no one went inside the crime scene until Dexter came, went in by himself, and then had time to damage the painting. That has never fucking happened in the history of this show. They have never stayed outside of a crime scene in order to wait for Dexter. Lazy writing. That's what that is.
This season was one of the worst. But at least they finally brought Deb in on the secret. I'll give it that.