‘An awkward customer?’

‘I’d say so.’

‘Stay on him,’ said Fry. ‘And let me know if you want to try a different approach.’

There were accepted strategies for dealing with awkward customers. They didn’t have to speak to the police, but different officers and different approaches could be tried. In some circumstances, they might decide to take an interest in another issue, such as whether his car was legally taxed and licensed. No undue pressure, obviously.

As a last resort, there was always the option of arresting someone so they could be questioned and searched. Without justification, they were open to the subject deciding to sue, and might have to pay a couple of grand out of court. But financially it was preferable to deploying expensive resources on long, fruitless enquiries when a line of investigation was blocked.

‘We should try to find these farm records,’ said Cooper. ‘I think Farnham was right about that, at least. If the records are anywhere, they’ll be inside the house.’

‘Well, I’ll help you later. At least it’s dry inside the house, if none too clean.’

But Cooper wasn’t paying attention now. He was looking at his feet.

‘You know, I don’t remember ever seeing mud this red before – not in this area. The real clay soils are further south.’

Murfin came trudging through the mud to hand Fry a list of the items that the forensics team had recovered from the skip. It was a very long list, but most of the material she could discount. She was only interested in what had come out of the hole, and the SOCOs had helpfully grouped some items together. These had been tipped on top of the skip in one corner, where a couple of planks had been laid as a runway to get a wheelbarrow up to the right height. There were stones here, some unidentifiable bits of rusty metal, a broken bucket, a packet of coffee filters, and some brown mason jars.

She read through the list again, more carefully, then turned to the rest of the material that had been felt less significant. The SOCOs had been right – they’d picked out the relevant items. They couldn’t list what wasn’t there.

Fry stared across the site at the body tent, where a forensic botanist was using a teaspoon to tease out plant fragments. She had a clear picture of Jamie Ward, squatting in the wet mud, staring in shock at the object he’d found in the trench. When he shouted, someone had run up to him, thinking he’d hurt himself, while Nikolai, the foreman, had been cursing in the background. All perfectly clear, but for one thing.

‘Gavin, have you got the list of builders’ names and addresses?’

‘I hope you don’t want them in English.’