Written in Bones by James Oswald

The roots of murder run deep... A body is found in a tree in the Meadows, Edinburgh's beautiful public park. The forensics suggest that the corpse has fallen from a height - but was it an accident or a shocking message? The dead man had led quite a life - a disgraced ex-cop turned criminal kingpin and, most recently, the head of a celebrated charity. As McLean investigates, his search takes him from the city's underworld - crossing paths with some of the most dangerous and the most vulnerable people in society - before taking him to the heart of a shadowy conspiracy stretching back years....