I can see how Polly was so disturbed by it, Perez thought. How she started to question her sanity.

‘You got Grace to record Peerie Lizzie’s song,’ he said. ‘But of course it didn’t sound right. She’s spent a lot of time in Shetland, but she hasn’t picked up the accent yet.’ He paused. ‘She and the Arthur boys were singing it the night Polly was lost in the fog and must have freaked her out big-style.’

‘When I went south, Grace wanted to stay with Jen Arthur and the boys and I thought another week off school wouldn’t do her any harm. Jen was happy to have her, and it’s an education in itself, isn’t it, living in Shetland? I didn’t know then that Eleanor had been killed and there was a murderer on Unst.’

‘It must have been in the papers in the south,’ Sandy said. ‘Once Hillier was killed too. Why wait until today to get in touch?’

Monica still looked out at the grey water. ‘I was scared. If you knew I was there the night Eleanor was killed – if you found my painting – you might accuse me of murder.’

‘Not if you were innocent,’ Sandy said. ‘You’d have nothing to fear, if you told us the truth.’

She turned back to face him. Her words shot towards him like the rain on the window. ‘Really? When I was a student I was assaulted by a lecturer. I went to the police that time. They believed a respectable lecturer over an unconventional art student and threatened that I could be charged with wasting police time if I didn’t withdraw the allegation. I wasn’t prepared to take the risk now.’

The room went very quiet. Behind the counter the coffee machine hissed.

‘Let’s go back to that meeting at the Hay’s Dock,’ Perez said. ‘Did you take photographs afterwards?’

‘Yes, Eleanor wanted some publicity images that we could release to the media before the show.’ Monica looked up. ‘She was already planning features in the broadsheets. How four metropolitan thirty-somethings believed that they’d seen a ghost.’

‘And one of the pictures was of her and Lowrie?’

‘Yes, Lowrie asked if he could have it. I emailed it to him. Why? Is it important?’

Perez didn’t answer. This was the photo that Lowrie had been staring at when Grusche went into his room before the party. The photo that had triggered Eleanor’s murder. ‘Tell me what happened the night of the party.’

‘Grace and I went into Unst on the ferry.’

‘You were seen by the Meoness teacher.’ Sandy seemed to wake briefly, then to settle back with his arms on the table. They’d all been awake all night. He looked like a nursery child ready to take a nap.