‘“Street girls” isn’t really a suitable euphemism out here,’ pointed out Fry. ‘Shall we call them sex workers?’

‘Prostitutes, if you like. But where would they do business?’

‘Wherever there are numbers of men with nothing much else to do.’

Cooper pictured Pity Wood Farm. ‘Targeting itinerant farmworkers, for example?’

‘Who else?’

At first, he thought it was a rhetorical question. But the tone had been wrong, and Fry seemed to be waiting for an answer.

‘Yes, who else?’ said Cooper, regarding her curiously.

‘All right. I was thinking about old-fashioned police officers who operate under their own discretion and run their own patch, with no questions asked.’

‘That old thing?’ said Tom Farnham. ‘Who would want that? It’s just an old skull. Some damn superstition of Derek Sutton’s. Mad bugger, he was.’

Farnham fidgeted with the spray can he’d been using to touch up a dent on the lawnmower. Its repair was nearly complete now. Its working parts gleamed with oil, and its paintwork had been cleaned and polished.

‘But you do have it, sir?’

Farnham sighed. ‘Don’t you need a warrant or something?’

‘Only if you don’t agree to help us. But why would you want to prevent us seeing this skull if it’s worthless?’

‘Why indeed? Screaming Billy, that’s what the old fool called it. Supposed to protect the farm from bad luck, or something. Raymond didn’t see eye to eye with him on that, not at all. He wanted it out of the house when the place was sold. Said he wouldn’t curse the new owners with it. Raymond, he didn’t care about anything else – he was glad to get shut of the place in the end. It was just that skull he had a bee in his bonnet about. He rang and asked me to get rid of it before the new bloke took over the farm. So I did him a favour, see? For old times’ sake, and all that.’

‘Very loyal of you, sir. And it’s still here?’

‘Yes, it’s still here.’

Farnham moved across to his work bench and took a key from his pocket. He unlocked a cupboard under the bench and withdrew a cardboard box packed with old newspaper. In the middle of the newspaper, something smooth and yellow nestled.

Cooper took the box from him and pulled on a pair of latex gloves. He carefully lifted the skull free and placed it in a plastic evidence bag. The bone was faintly yellow, like paper that had been left in the sun.

‘You couldn’t sell it, then?’ said Fry.

‘What?’

‘That’s what you were hoping for, I imagine.’