I find myself reading an instalment of the Hidden Norfolk police procedural series, starring DI Tom Janssen, every few months, and let me tell you, it is a distinct pleasure. Janssen, unlike many fictional detectives, is a straight-up mensch, a balanced soul somehow driven to employ his intelligence and energy to track down murderers. His eclectic crew of detectives are a readerly pleasure to follow. “A Dark Sin” is Janssen’s eighth outing and it is a solid hitter, rocketing along at pace and tantalising the reader with clues until the surprise reveal. When a journalist is found dead in a remote spot, underneath a noose, on the day of a teenager’s suicide years ago, Janssen swiftly diagnoses murder and begins an arduous trawl through the local community and into the shrouded past. Given the rapidly growing length of this series, I recommend beginning at One Lost Soul, Book One, and catching up fast, so that you too can bask in the ongoing adventures of DI Tom Janssen.