The only woman staying at the centre was Sarah Fowler, but she was as tall as her husband, and in a bulky jacket and a hat, from a distance it would be impossible to tell the difference. But from the hill the walker would have seen Poppy clearly, especially if he had binoculars. Perez was pleased the girl would be out on the boat early the next morning.

‘Did Angela say anything to you in the week before she died? Anything to explain why she was killed?’

‘Nah, she didn’t pay much attention to me. I mean, she poked away about my boyfriend and what a loser I am, but looking back I don’t think her heart was in it. She had something else on her mind.’ There was a pause, a moment of honesty. ‘That’s probably why I tipped the beer over her. Better that she hated me than acted as if I wasn’t there.’

At ten o’clock, Perez decided he would leave the residents in the company of Rhona Laing and return to the crime scene. She was untroubled about being abandoned and as he left, she was organizing sleeping accommodation for herself, Sandy and Vicki.

‘Absolutely not a dormitory,’ he heard her say to Maurice. ‘At least not for Ms Hewitt and me. Single rooms. Preferably with showers. You can put DC Wilson wherever you have room.’

Perez walked through the moonlight to the Pund. There was already a frost and a thin shell of ice on the water in the mire. His earlier conversations with the field centre residents ran through his mind. What had he missed? What had provoked another murder? Perez still thought the killer was rational. These weren’t the actions of the tabloid psychopath. There’d been no sexual assault and, certainly in Angela’s case, no more violence than was needed to kill. That had been controlled, not the outburst of a spoiled teenager. He thought again he could safely send Poppy away from the island to her mother. After their conversation he had no sense of her as a murderer. It seemed to him that Jane had been stabbed because she posed a threat to Angela’s killer: she’d seen something or heard something or worked out the identity of the perpetrator. But even if she hadn’t been a victim in her own right, there’d been a ferocity in the attack that was different and Perez found that confusing.