‘No.’ That at least was something Perez had discounted almost immediately. His father had been at Springfield when Angela Moore had been killed and if he’d stabbed Jane Latimer to prevent her from talking about his affair, he could have taken the jewellery out of the wooden box then. Besides, the show with the feathers wasn’t his style.

‘Then charging doesn’t come into it,’ Sandy said. ‘But if he knew the woman then he might have something useful to tell you. It would be wrong not to ask him about her. He’s an important witness.’

‘He’s tampered with a crime scene,’ Perez said. ‘Perverted the course of justice.’

‘Maybe,’ Sandy said, ‘if you have got this right, he’s trying to save his marriage.’ He paused. ‘And his son from embarrassment.’

They sat in silence and watched a huge orange sun rise over the sea beyond Sheep Rock. In the distance there was the sound of an approaching plane.

Perez went to the airstrip to watch the plane arrive. It must have left Tingwall at first light and it certainly wasn’t a regular scheduled flight. He met Dougie Barr, the fat birder, on his way; the man was flushed despite the cold and out of breath.

‘I’ve just been up to Golden Water,’ he said, the words coming out in short, painful bursts, ‘to check that the swan’s still there.’

‘And is it?’ After a night of anxiety about his father, Perez saw the birdwatchers now as an amusing distraction. He’d always found the obsession of these men faintly ridiculous. He realized that they were mostly men. Angela Moore was a rarity.

‘Yes. Just where it went to roost yesterday evening.’

‘You’ll take them straight up to the north end and then back to the plane. No detours. Otherwise the flights will be stopped.’

‘I’ve explained all that to them.’ They both stepped off the track to allow Dave Wheeler to drive past.

There were still signs on the airstrip of the preparations for the emergency flight the night before – piles of ash where the fires had been lit, scorched grass. The plane circled the strip and came in low to land, smooth and easy. Tammy Jamieson’s wife turned up, not in the van – Sandy was still using that – but in a gold Ford Capri with the wheel arches eaten away by rust. She parked just where Perez was standing and wound down the window. She was a Fetlar woman; she and Tammy had met at school.

‘Glad to have Tammy out with the boat?’ Perez asked.

‘Aye, he’s like a bear with a sore head if he doesn’t get on to the water every week. And I’m glad of the peace. I love him to bits but we all need some time on our own.’

‘Anyone you know coming in on the flight?’