‘I can’t,’ said Grier, getting to his feet. ‘Not again. Just press the play button when you’re ready to begin.’

There were murmurs of agreement from the other officers and they moved away from the desk. Although they remained in the incident room, it seemed to Tina as though they were keeping as far away from the laptop as possible, as if whatever was on it was somehow infectious.

MacLeod leaned forward and pressed the button on the screen. Then he and Tina stood side by side as the screen lit up to reveal a lengthways shot of a young woman lying on a bed. Tina immediately recognized her as the final victim, Adrienne Menzies, a thirty-three-year-old accountant from Highgate with hair the same dark colour and style as her own, and whose DNA was on the hammer found at Kent’s apartment. She remembered the bed’s expensive yet old-fashioned teak headboard, which she later found out had been handmade by Adrienne’s father. It was always the little details that stayed with you, even amid the horror. And the horror here was unrelenting.

Adrienne was naked and bound to the bed with black PVC bondage straps of the kind Kent had used in all but one of his murders, and her mouth was gagged with duct tape. The picture quality was very good and Tina could make out the bruises and scratches on her thighs and round her breasts. The camera moved in slow, jerky movements more akin to a homemade film as the person holding it walked carefully round the edge of the bed, filming Adrienne’s vain struggle to free herself from the bonds that kept her firmly in place. Beneath the gag, her muffled cries of fear grew steadily more desperate and her eyes widened and bulged as if the fear in them was a living thing trying to squeeze its way out.

The cameraman stopped moving and focused in on her face so that it filled the screen entirely with a pleading expression Tina found hard to bear because she knew exactly what was about to happen to this pretty young woman who, until a few hours before this, had lived a generally happy, ordinary life with family and friends who cared for her. Tina had been at the murder scene. She had stood in that bedroom, looking down at the unrecognizable face in a mask of coagulated blood; the thick splatters on the bed linen and the walls; the long smear only just visible on the teak headboard. .