''The Price of Darkness'' is the ninth in a series of police procedural novels by Graham Hurley. Although I've not read any of the preceding books, I was easily able to pick up the thread of this chronicle of South Coast crime. Moving along at a leisurely pace, the novel comprises two main strands: the investigation of the murder of a property developer, and the adventures of Paul Winter, a former copper who's now working for Portsmouth's biggest criminal family.