OK, I'm having to do this from memory as have only just worked out whose book it is and I read it back in April...
Good read - I like a nice bit of crime fiction. The one thing that annoyed me slightly was the over-abundance of backstory - lots and lots of talking about the characters' relationships too each other, how they got that way - or even more annoyingly, sometimes making references to shared experience with no explanation. This is one of the slight hazards of a series - how do you cater for the reader who hasn't started from book 1? - but I did think he could have handled it better. This narrative clutter did also mean it was quite slow to really get going, despite starting with a bang.
Still, it really kept me interested. I now can't remember whether this was one of those books that had the now somewhat over-worn device of a good guy turning out to be a bad guy - I hope it wasn't as I definitely left this with an overall positive impression.