As he listened with the other officers in the room, Cooper became aware for the first time of the complications of the inquiry. He’d been a DC on the division then, but too lowly in the hierarchy to grasp the overall picture. He recalled taking witness statements that had provided nothing of any value to the investigation, talking for hours to people who had no useful information to give. He’d been sent back to ask more and more questions, until he felt he was scraping the barrel and not producing a thing for his efforts.

So much was known about David and Trisha Pearson after all those months of careful investigation. Yet so little of it had proved to be of any use in finding them.

David Pearson, aged thirty-six, a senior adviser with Diamond Hybrid Securities, based in London. His wife Patricia Pearson, known as Trisha, aged thirty-three and working in public relations. A couple with no children, but a nice home in the Deepdene Wood area of Dorking, Surrey. They had spent a summer holiday in the Seychelles that year, but had chosen to take their Christmas break in the Peak District.

On the night they disappeared, the Pearsons had been to the George in Castleton for dinner. Mushrooms in peppercorn sauce, Bantry Bay mussels, honey-glazed ham shank. At least they’d eaten well on their last night, not to mention the two bottles of wine they’d drunk.

At the end of the meal they had set off to walk back to their holiday cottage on Brecks Farm, near the village of Peak Forest, a distance of about three miles from the George. And that was the last anyone saw or heard of them. Not a phone call, not a single confirmed sighting, not a shred of paper trail to follow.

Hitchens tried to summarise the main facts of the case as best he could. The DI had been putting on weight recently, and there were traces of grey in his hair. His manner suggested this was one inquiry that had contributed to his premature ageing.

‘The Pearsons stayed late over their meal at the George, finishing the extra bottle of wine,’ he said. ‘They stayed much too late. By the time they left the restaurant, the snow had started. They were foolish to attempt to walk back to the cottage across the moor in those conditions. It wasn’t surprising that they never made it. The mystery was what happened to their bodies. They were never found.’

‘So what were the theories?’ asked someone.

‘There were several. But they boil down to two basic scenarios.’

Hitchens turned to use the whiteboard, perhaps hoping that it would draw the attention of all those eyes away from him for a few minutes. He wasn’t a natural public speaker, which was a drawback in anyone with aspirations to become a senior officer. The TV crews would be arriving before long, and the DI wasn’t the sort of man to make a good show in front of the cameras.

‘Scenario number one,’ he said, scrawling the phrase as he spoke. ‘The Pearsons lost their way in the snowstorm and died somewhere on the moors before they reached their destination. In that case, we would normally have expected to find their bodies, which we didn’t. So, what then? Well, they might have strayed so far off their route that they hit the flooded open-cast workings at Wolfstones Quarry, which were partly frozen over. Or they could have taken shelter in a cave, or the entrance to one of the old lead mines, and gone in too deep. They wouldn’t be the first to go in and never come out. Some say that a party of cavers will turn up their bones one day.’

‘Did we send divers into the quarry?’

‘No, it wasn’t feasible. The edges of the water were searched, but there was no indication at what point they might have gone in. It isn’t a small body of water, you know. Without a reference point to start from, it was futile. You could tie up a team of divers for months without anything to show for it.’

DCI Mackenzie looked up at the pause. He was reading from a file, as if following the explanation by Hitchens and comparing it to the written record.

‘There was another theory too, though,’ he put in.

Hitchens sighed. ‘Yes, this was the one that seemed to find most favour at the time. It was the easiest option, of course. Not that I’m saying it influenced the outcome of the inquiry exactly, but, you know … it might have been a factor.’

‘And this theory was …?’ prompted Mackenzie.

‘Okay. Scenario number two.’ Hitchens wrote it on the board. ‘The theory that the Pearsons disappeared deliberately, did a bunk and changed their identities. The suggestion was that they wanted people to assume they’d died an accidental death.’

‘Why would they do that, sir?’

The voice came from the back of the room, and Hitchens scanned the faces, looking for the speaker. Cooper recognised it as Luke Irvine. He turned and saw Irvine sitting with Gavin Murfin on the back row. That could be an unholy alliance.

‘When the police in Surrey looked into their backgrounds, they found evidence that David Pearson had been defrauding his employers, and their clients,’ said Hitchens. ‘It seems he’d been sifting funds out of client accounts for years, bit by bit. Some of it was in various savings accounts under his and Trisha’s names, but the suspicion was that far more money had been taken that wasn’t accounted for. It might only have existed in the form of cash.’

‘So they staged their own disappearance and vanished with the cash to make a new life for themselves somewhere?’ asked Irvine. ‘Anywhere in particular?’

Hitchens shrugged uncomfortably. ‘Spain, South America. Who knows?’

‘There was the Canoe Man case a couple of years before.’

Becky Hurst. That was a voice Cooper didn’t expect. He swivelled and caught Hurst’s eye. She gave him a small smile, perhaps intended to be reassuring.

‘Yes, I’m sure we remember that,’ said Hitchens.

‘In that case, he almost got away with it,’ pointed out Hurst. ‘If he hadn’t let the estate agent take his photograph when he bought the apartment in Panama, he might still be there. He didn’t realise they were going to use it in their advertising on the internet. But the Pearsons … they would have learned from what he did wrong.’

‘If that’s what they were planning.’

‘How did they get away from the area, then?’ asked Hurst. ‘Was there any evidence they actually did go back to the cottage that night? Or did they have another vehicle kept handy somewhere?’

‘We don’t know.’

‘I suppose they were smart enough to cover their tracks pretty well.’

Hitchens hesitated, and glanced at Mackenzie, who didn’t react.

‘This was only a theory,’ he said. ‘It was never established as a fact. The reality is, we don’t know what happened. We need that information first.’

‘Before we do what? Write them off as accidental deaths? Just another misadventure?’

‘That would be up to the coroner.’

Diane Fry hadn’t yet spoken. Cooper could see her sitting to one side, near the wall. Like Mackenzie, she had been slowly turning pages of the file. He knew Fry well enough to be aware that she had a terrific memory for details. The significant facts of the case would already be logged in her mind.

When she did speak, Fry chose her timing perfectly – not raising her voice, but inserting her question precisely into the momentary silence.

‘Two people went missing in bad weather, and there was no proper search?’

Hitchens looked surprised.

‘I wouldn’t say that. It just wasn’t feasible to mount a full search operation straight away, given the conditions. The helicopter couldn’t fly, and it was pointless trying to get boots on the ground. We would only have been putting more lives at risk.’

‘According to the incident log, it was five days before the search of the moor was completed.’

‘We did our best. Buxton Mountain Rescue went up there. They did a sweep of the immediate area as soon as the snow stopped and they had daylight hours to work in. Cave rescue checked out the disused mine shafts. No signs of the missing people. There was nothing. But, yes – it was five days before we were satisfied that we’d done a thorough search.’