In many ways (in fact in most ways) this is a terrible book. It’s ludicrously cliched, to the extent that at times it reads like a parody of a tough LA cop hunting a serial killer novel. I guessed the twist half way through (and I never guess twists!) and the prose is awful. The book has so much unnecessary description of irrelevant details that it could probably have lost 100 pages without losing any story. 
And yet it is kind of fun. It’s so easy to read that you could do it when you were asleep and it has the same kind of pulpy appeal as a Doc Savage book. You know it’s stupid but sometimes that’s alright.