Fiona Cummins delves into the seam of darkness that runs through us all as a detective hunts down a twisted killer with a macabre obsession . . . On still nights, when the curve of a winter moon is smudged in the flow of the River Quaggy, the dead clamor for him. And sometimes he coaxes the living to join them. To other people, his victims might be mere medical oddities. To him, they are fascinating specimens, worthy of display. Above all, he is a...