He took a chance to get into conversation with the dog handler. Cooper liked to hear about other people’s specializations. One day he’d probably have to choose one himself. A year or so ago, he’d been assigned to the Rural Crime Unit, and he’d expected it to be the first step towards a transfer. But the subject hadn’t arisen since, and it didn’t do to make enquiries, in case it tempted fate.

‘The dog’s brilliant,’ said the handler. ‘Nose like a radar. She can detect a decomposing body at the bottom of a lake, just by sniffing the bubbles on the surface.’

‘You’re kidding.’

Cooper looked at the German Shepherd sitting quietly by its handler’s side. He thought what the dog did with its nose was better than radar, actually – but he couldn’t think what else to compare it to.

‘But it’s not just managing the dog,’ said the handler. ‘Archaeological field techniques can be useful in this job. We’re trained to analyse vegetation and changes to the landscape caused by burials.’

‘How do you do that?’

‘Well, above a grave the vegetation is poisoned at first by too much raw nutrient in the soil. From the corpse, you know.’

‘Yes.’

‘But as time passes, the nutrients break down, and plant growth gets unusually lush. So a very green patch in an area of sparse vegetation can be a clue to the site of a grave.’

Cooper studied the dog handler. The man had a Scots accent, but that didn’t necessarily give credence to the pig rumour. He wasn’t even in uniform, but was wearing a blue boiler suit.

‘That makes sense.’

‘It doesn’t always work, though. We’ve been out to sites where the corpse has only been in place a few weeks, but the soil and vegetation has settled back into place. It’s incredible how quickly that can happen. Then you’ve got a real problem.’

They both gazed down into the woods, where the university team and the SOCOs were still working.

‘Sometimes, you know,’ said the handler, ‘it’s as if the landscape just accepts a body and digests it completely, given time.’

Fry walked across and drew Cooper away from the dog handler. ‘The opinion of the experts is that any missing bones could simply be a natural result of a body being reduced to a skeleton,’ she said, as if he’d asked her the question. ‘No skin and muscle to hold it together. But I still think you’d need to physically separate some of them from the skeleton. Don’t you?’

‘You think someone might have come across the skeleton and decided to take a few trophies instead of reporting it?’

‘It’s a possibility. But you know perfectly well it could also have been somebody who knew the remains were there, and simply waited until the time was right.’

‘Who would do that?’