‘It makes a kind of sense to me,’ Willow said. ‘They both liked a drama – the fights, the falling out, the reconciliation. I can understand how Eleanor would have enjoyed the challenge of convincing Ian that something supernatural was happening in Unst. She’d be able to mock him for the rest of their life together. And her whole existence was a theatrical production, so she’d have relished setting up something like this.’ She paused. ‘In her documentary I guess she wanted to prove that we need to believe in something other than the everyday world, to show that we’re looking for an explanation for random events. It doesn’t seem too daft, as theories go. Folk were always turning up at my parents’ commune searching for answers.’

Perez thought this story had started with a deception and it was all about illusion and distorted perception. Strange shadows and half-spoken lies. ‘I was never convinced when Lowrie said Eleanor hadn’t discussed the project with him. That defied belief. She knew he’d do whatever she asked him to. He was Eleanor’s champion, her knight in shining armour, charging to the rescue of her failing company.’

Willow reached out and poured herself another dram. For all that she was lanky and awkward to look at, Perez thought there was a grace about the way she moved. He looked at the water again. The Hjatland was already out of his line of sight.

‘Why didn’t Lowrie tell us all about the hoax, when Eleanor’s body was found? There was no reason to keep it secret after that.’ It was Sandy again, full of common sense.

‘Because Grusche persuaded him that it would be a mistake and his involvement might turn him into a suspect. He wasn’t exactly in the right frame of mind to make a rational decision. Bullied into marrying Caroline. Convinced by two strong women that his future lay in Shetland. And imagine the shock of finding Eleanor dead! The love of his life. His adolescent sweetheart. He’d grown up doing exactly what his mother wanted him to. This wasn’t going to be the time when he’d stand up to her.’

‘Do you think he guessed that Grusche was a killer?’

Perez hesitated. It was something he’d been thinking about since they’d first interviewed the woman. ‘Maybe. Deep down. But it wasn’t something he could afford to admit to himself.’

‘I still don’t quite understand what happened last night. All that unnecessary melodrama.’ Willow was lying flat on the floor now, and fibres from Perez’s shabby carpet had clung to her sweater. ‘Why did Grusche attack Polly? Where on earth did that come from?’