‘She’s a school cook,’ Sandy said. ‘In Aith. Nothing to do with the water scheme.’

‘But where Markham’s body was discovered. Another coincidence?’

‘This is a small place.’ Sandy shifted uneasily in his seat. ‘People bump into each other.’

‘So they do.’ She flashed him a smile, but Perez could tell that she was unconvinced. She didn’t believe in coincidences.

‘And is it just chance that a woman looking very like the Fiscal had coffee with Markham the morning he died?’ Willow reached out and took an oatcake from the table and ate it dry. No butter. No cheese. Was she concentrating so hard on the facts of the case that she didn’t notice? ‘Then the body was found on her doorstep when the fog cleared later in the day.’

‘You have Rhona Laing down as a suspect?’ Perez thought she was mad.

‘Not that,’ Willow said. ‘No, maybe not that. But she’s involved. She knows more than she’s telling us.’

There was a moment of silence. Absolute silence. No wind outside. No traffic noise.

‘Anything from James Grieve and the postmortem?’ Perez asked.

‘Nothing helpful. Nothing that we didn’t know already. Markham was killed by a violent blow to the head and placed in the boat postmortem. The pathologist couldn’t pin down time of death more accurately than we already had it – so between Markham leaving Sullom Voe in the afternoon and his body being found by the Fiscal at six-thirty. His last meal was fried fish and chips.’ She paused. ‘We don’t know yet where he ate that.’

‘Any more detail on the murder weapon?’ Perez was finding this discussion easier than he’d expected. After Fran’s death he hadn’t believed he’d be capable of talking about violent death in a dispassionate and professional way again. But this was like a habit, a learned script: the routine questions formed in his mind without too much thought. A performance.

‘Grieve thought a spade or a shovel. Heavy, and wielded with considerable force. We need to find it. Something else for tomorrow.’ She stretched and Perez thought again how tired she looked.

‘Do we think the murder was planned?’ Perez was talking almost to himself. ‘That sort of weapon could be something you’d pick up on the spur of the moment, if there was a fight.’

‘I suppose that’s possible.’ Willow frowned. ‘But there were no other signs that there’d been a scrap. No grazes on Markham’s knuckles and no other injuries. We’ll organize a search for the weapon tomorrow.’

‘I don’t think you’ll find it.’ Perez stared at the fire. ‘Anyone with a peat bank or a croft would have something like that in their house.’ He felt he was being negative and unhelpful. ‘You said there was a briefcase with him in the boat. What was inside?’