This is a intense blend of psychological thriller and police procedural set in Liverpool. Aside from a hunt for a sociopath serial killer, known as the Thorn Killer, there is the mystery and intrigue of the relationship between DCI Greg Carver and DS Ruth Lake, underpinned by distrust, lies, secrets and deception. Carver is the lead investigator of the killer who has tortured and killed 5 women, tattooing them painfully using a thorn as the stylus, experimenting with differing inks mixed with a variety of plant poisons. Carver falls apart after the fifth victim, Kara Grogan, is chosen because of her strong resemblance to his wife, Emma, and is found deliberately posed, wearing her earrings. He is separated from Emma, binge drinking, running a case which he documents officially at work conscientiously, but which is entirely fictitious, whilst at home he has his real investigation notes.
The story opens with DS Ruth Lake tampering with a crime scene where Carver has been shot, removing the gun and the private case notes. Lake is ex-CSI forensic investigator turned detective, she can read people, and can determine when she is being lied to and maintains an impressive calm impassivity in her efforts to get to the truth. Thanks to Lake, Carver survives, but his memory is shot to pieces and he cannot recall the events surrounding his shooting, although he is less than forthcoming about what he does know. Lake and Carver lie to each other, as Ruth picks up the trail for the serial killer as she digs deep into the life of Kara and the other victims. The murder of businesswoman Adela Faraday begins to reveal connections with the hospitalised Carver and some of his secrets. Carver begins to recover the occasional memory as he and Ruth continue their investigation to uncover the killer. In the meantime, the macabre killer begins to focus on Ruth, whose life becomes endangered. This is a intelligent serial killer, highly manipulative, completely obsessed by accessing the secrets of the victims, the lives they keep secret from their families and others.
This is a disturbing and unsettling read, with its fascinating and flawed protagonists whose lives and relationship with each other is mired in darkness. So much so that the serial killer's interest in them is inevitable, and it makes for compulsive and compelling reading. The author has created a mentally unhinged and controlling killer whose behaviour and thinking gets under your skin and creeps you out, particularly given the atmosphere of menace that pervades the novel. I am not sure if this is the first in a series, but I really hope we get to renew our acquaintance with Carver and Lake, they make an unusually gripping pair in crime fiction. An absorbing and entertaining read that had me appreciating the author's skills in plotting and characterisation. Many thanks to Little, Brown for an ARC.