I... liked this?
I did, actually. And the whole conceit of the protagonist being a sociopath is interesting, because you are left to root for and empathize with a character who has no empathy.
But I will say for certain, when it was revealed that the killer was actually a monster, as in supernatural creature of some sort, rather than a garden-variety serial killer, I was pretty shocked. The first third of the book is so rooted in reality, so when that turn happens, I actually went back to reread and make sure I hadn't missed something, like John's imagination supplying all this.
Interesting, for sure, a horror story told in a clinical, emotionless way.
I'll probably read the next in the series, just to see.