No shred of evidence

"New York Times bestselling author Charles Todd brings back Scotland Yard's Ian Rutledge, who must unravel an unsolved, old case before he can bring a murderer to justice"--

On the north coast of Cornwall, an apparent act of mercy is repaid by the arrest for murder of four young women. A shocked father calls in a favor at the Home Office; Scotland Yard is asked to review the case, but Inspector Ian Rutledge is not the first Inspector to reach the village. Told the case is all but closed, Rutledge will require all his skill to deal with the incensed families of the accused, the grieving parents of the victim, and local police eager to see these four women sent to the infamous Bodmin Gaol. Then why hasn't the killing stopped?