Then there was lots of waiting about in an office in the Gilbert Bain hospital. Gallons of tea. Distant noises – the clang of a tea trolley hitting a metal bedstead, cheerful voices. The doctor, who looked to Perez no more than a teenager, repeating over and over again that there had been nothing they could do. He’d been with the team that had come into Fair Isle in the helicopter and in the morning when it was getting light and James was telling Perez they should go back to the house in Lerwick, because Jimmy needed to eat and to rest, the doctor clung onto them. As if he was the bereaved person. And Perez didn’t want to go. Because somehow this young man, with his acne and his bad breath, was the last link he had to Fran.

In the hospital they’d offered Perez pills to help him sleep, but he’d refused them. He didn’t deserve to sleep again. He sat in the narrow kitchen in his house by the water in Lerwick watching his father frying bacon and eggs. The older man’s face was grey. He was exhausted but his movements were deft. He warmed the plates, flipped the oil over the egg to make sure it was cooked. As soon as the meal was over he washed the dishes. ‘Why don’t you get some rest?’

While his father was lying on Perez’s bed, the detective replayed the moments of Fran’s death in his head, over and over again, like a film on a loop. Maybe thinking that eventually there would be a different ending to the story. Knowing that was crazy but wanting to believe it.

Sometime in the afternoon Sandy turned up at the house. He blamed himself for Fran’s death. Perez saw that as soon as he came through the door. He was shaking. ‘You told me to look after her.’ He couldn’t stop saying that. Not the same words but meaning the same thing. Why did people feel the need to speak so much?

In the end Perez said, quite roughly: ‘You weren’t holding the knife, man. Give it a rest.’

So they sat in silence, drinking more tea. Perez would have liked a proper drink, but knew that if he started he wouldn’t be able to stop.

‘We brought all the witnesses out in the boat,’ Sandy said. ‘They’re making statements in the station now.’ He paused. ‘I wondered if you fancied sitting in. Not to do the interviews, of course. And not Fowler, that wouldn’t be right. But it’s your case.’

‘Worried you’ll miss something, Sandy? Worried you might have to take responsibility at last?’ His grief was liberating. He’d never been so cruel before to Sandy. Now he felt as if he had licence to do or say anything he wanted.

Sandy’s face went very red, streaky as if he’d been slapped and the finger marks still showed. ‘Aye,’ he said. ‘Something like that. But I wanted to give you the chance to be there if you wanted.’

‘Sorry. You’re right. I would like to sit in.’ A lie, of course. He didn’t care enough to want anything. But Perez thought it would be better to go with Sandy than to stay here as dusk fell, he and his father sitting on either side of the fire, like two lonely old men, not knowing what to say to each other.

In the police station, where once he’d been so at home, he felt like a stranger. He was a different person. He saw Fran everywhere: standing behind the custody sergeant at his desk, laughing with his colleagues in the canteen as Perez walked past. He thought: Is this how it’ll be for the rest of my life? I’ll be haunted by her.

Her ghost hadn’t made it to the interview room and for that he was grateful. He tried to focus on the matter in hand in case she slipped under his guard and found him there too. There was a detective Perez didn’t recognize, sitting at the desk alongside Sandy. Perez assumed he was from Inverness, maybe even Roy Taylor’s replacement, but he didn’t care enough to ask. The stranger might as well not have been there: Sandy did all the talking. And he was bloody good, Perez thought, taking a stolen moment of pleasure to think Sandy had been well taught. Perez pulled a seat into a corner. Anyone looking in would have assumed he was sleeping, but he listened, caught up in the stories beside himself. They spoke to Hugh Shaw first.

‘Tell us about the blackmail,’ Sandy said. ‘It’ll all come out now. Fowler’s talked to us. No point hiding.’

Hugh stared at Perez, but didn’t mention his presence. He slouched across the table towards Sandy. He reminded Perez of the cocky teenagers he’d often picked up in the city. No discipline, no work, believing the world owed them a living. But those young men had grown up on sink estates with little prospect of work. Hugh Shaw didn’t have that excuse.

‘I knew Angela wouldn’t miss the money,’ he said. ‘She was minted. She made more from one TV documentary than a year’s salary at the field centre.’

‘So tell me.’

‘It was all about the slender-billed curlew,’ Hugh said. ‘The bird that made her famous.’

‘What about it?

‘It was lies. She didn’t find it. The fame, the money, the reputation as a great scientist, it was all built on a lie. She stole another man’s research.’

Perez understood why the woman had been so unhappy, why she’d married an older man just for convenience. Her work had been the most important thing in her world and she’d compromised it. She had no pride left. Perhaps she saw the baby as a chance for a new start. Something honest and real. Perhaps it was a biological imperative that had driven her, a desperation to give birth. Fran had been experiencing something of that sort in the last few months. Again, he tried to banish Fran from his mind.

‘How did you find out?’ Sandy leaned across the table towards Shaw, his elbow on the table.

‘There was a Brit in Tashkent. An ex-pat doing something dodgy with the Russians, but also a birder. We sat in the Rovshan Hotel one night, drinking local beer and Johnny Walker Black Label, and he told me the whole story. John Fowler had tracked down the curlew population. Angela was looking for the species. She wanted something big to make her name. But he got there first; he found the birds by looking for the food they took, some kind of insect.’

Mole crickets, Perez thought. Fowler was still trying to interest the scientific world in his story. There’d been a letter saved on his computer, but none of them had recognized the significance.

Hugh continued: ‘Fowler was an amateur lister, in a hired car, wandering across the desert, hoping for the big story to make his career as a natural history journalist. He didn’t even have a degree! She had a PhD and a research budget and he beat her to it!’

‘But he never got the glory he deserved.’ Sandy again. That’s just what I might have said, Perez thought. You’re just speaking my lines.

‘Angela published first. And who was the establishment going to believe? Fowler already had the reputation as a bit of a stringer. Angela made sure nobody took him seriously again by spreading rumours around Shetland about rare birds he was supposed to have claimed. He became a laughing stock.’

It became his obsession, Perez thought. At first I thought he was driven by the need to see birds, like the twitchers who piled into Fair Isle to see the swan. But it was about revenge. He blamed Angela Moore for everything that had gone wrong in his life. For the dead baby and the dead marriage as well as all his lost dreams.

‘And you thought you’d take advantage of the situation?’

‘I’d always wanted to visit Fair Isle. I’d run out of money and my father refused to give me more.’ Hugh looked up and Perez saw an attempt at the old smile. ‘Tight bastard. He could have afforded it. So yeah, I thought it was worth a go. I wasn’t greedy, only asked for a couple of grand to tide me over. I didn’t expect Fowler to turn up though.’

‘That must have been a shock to Angela too.’

‘You could say that! Maurice took the booking and suddenly Fowler was there in the common room when she came through to do the log. But Fowler was pleasant to her. Polite. Calm. He certainly didn’t give the impression that he was out for revenge. Maybe she thought he was a good man, who wouldn’t harbour a grudge. He went to church every Sunday. Perhaps he was into turning the other cheek. She was jittery though. Everyone thought she was moody because Poppy was staying in the lighthouse, throwing her tantrums, but that wasn’t it at all.’