Love Like Blood by Mark Billingham

A BLOODY MESSAGE
As DI Nicola Tanner investigates what appears to be a series of organised killings, her partner Susan is brutally murdered, leaving the detective bereft, and vengeful.

A POWERFUL ALLY
Taken off the case, Tanner enlists the help of DI Tom Thorne to pursue a pair of ruthless killers and the broker handing out the deadly contracts.

A CONSPIRACY OF SILENCE
As the killers target their latest victim, Thorne takes the biggest risk of his career and is drawn into a horrifying and disturbing world in which families will do anything to protect their honour.

(Description courtesy of Little, Brown)