‘What might Joseph have done that he could be blackmailed? You’re not saying he killed Mima?’

‘No!’ Sandy said immediately. ‘Not that. Not deliberately.’ He paused. ‘I’ve been going over and over it in my head. Wild ideas. Just churning round and round and making no sense at all. I thought the drink would give me some peace from it.’

‘Let’s look at them then. The wild ideas.’

‘My father could have killed Mima by accident. A mistake. Hattie saw him and so he killed her too. You said yourself he was at Setter the night she died.’

‘But he was in his house the whole of the evening of Mima’s death, watching television. Your mother confirmed it.’

‘Of course she did. She’d lie for us all.’

Perez smiled. ‘So she would. What’s the next wild idea?’

‘Could the killer have mistaken Mima for Hattie? They were both small and slight and Mima was wearing Hattie’s coat. Mima was out in the field next to the dig – Hattie would have had more reason to be there.’

‘It’s something I’ve thought about,’ Perez said. ‘But what reason could your father have for killing Hattie?’

‘None at all. He hardly knew her. Another crazy idea.’

‘Pretty crazy.’ But Perez thought Sandy wasn’t doing badly. The ideas the man had come up with had floated around in his head too. ‘Anything else?’

‘Nah,’ Sandy said. ‘That was about as far as I got.’ He gave a self-deprecating grin. ‘Not much of a detective, huh? Maybe I should give up policing and take up crofting after all.’

‘I think perhaps you’re overreacting about the sale of your grandmother’s home. Hardly surprising. You were very fond of her.’

‘Things aren’t right at home,’ Sandy said suddenly. ‘I hate it.’

‘Joseph and Evelyn are under a lot of strain. Things will sort themselves out when this is all over.’

‘Will it ever all be over?’ Sandy was almost sober now, but gloomy. ‘I’m not sure how anyone on Whalsay will cope if we don’t find out what happened.’

‘They’ll cope if they have to,’ Perez said. He thought the islanders had suffered worse than this. The fracturing of a community during the fifteenth century. The huge storm that had killed half the male population of Whalsay at the end of the nineteenth century, when boats out to the fishing had capsized under freak waves. The murder of the young Norwegian from the Shetland Bus during the war. ‘But I want to know. Not for them but for me.’ He looked at Sandy. ‘What are your plans for the rest of the night?’

Sandy shrugged. ‘I was going to stay in town but I’ll only carry on drinking. Maybe I’ll get home.’