>I did read an interesting theory that the killer could be
>Frank, that he had a split from reality during the traumas of
>his childhood, and that he could be unaware of what his other
>self is doing. That may be a little cliche for my taste (the
>old "the detective is the murderer!" thing), but I trust
>Pizzolatto, frankly.

I had thought they might be setting it up so that Paul did it: 1) why the guy in the mask doesn't kill Velcoro, a fellow cop, 2) the guy sets the car on fire then escapes, and then Paul wakes up the next morning not remembering anything, 3) Paul's motorcycle is "stolen", but maybe he rode it somewhere during his blackout and left it near a crime scene. It might also explain why they show Dixon following him, taking pictures. The mayor probably knows what's going on and what's to keep tabs on him/have blackmail material.

I agree that it would be cliche, but I could see it shaking out that way.