Being a member of the herd was a primal instinct – probably the deepest, most powerful instinct of them all.

‘If you do go, Diane,’ said Hitchens, ‘we’ll miss you.’

‘They called him Billy,’ said Cooper, the moment Fry entered the CID room. ‘Screaming Billy Sutton. But of course he probably wasn’t a Sutton. He could have been anybody. Anybody at all, Diane.’

Fry jumped as if she’d been shot. ‘What the hell are you talking about, Ben?’

‘The landlord of the Dog Inn said something about a Billy. At first, I thought he might have meant another brother, or a son. But there’s no indication of a William Sutton. So this must be him.’

She had never seen him so animated. He was running around the office like an excited puppy, yapping at anyone who would listen. But what was he yapping about?

‘Ben, slow down. Explain yourself properly.’

Cooper looked hot and breathless, as if he’d been running. ‘It’s like Dickie of Tunstead, you see. There’s a place called Tunstead Farm, up in the north of the county near Chapel-en-le-Frith. Now, that one is quite famous. There’s some doubt whether it’s male or female, but locally it’s always been known as Dickie. A previous owner of the farm was murdered in his bed in an ownership dispute –’

He paused to take a breath, and Fry held up a hand like a traffic officer, speaking louder to drown him out.

‘Ben, stop.’

‘The Suttons must have managed to keep this one quiet, though,’ he said. ‘It was known about locally, but everyone seems to have been reluctant to discuss it. Superstition, of course. Careless talk, the Scottish play, all that sort of stuff.’

‘For God’s sake, will you just stop? Stop!’

‘Screaming Billy was supposed to …’ Cooper finally ground to a halt and looked at her in amazement. ‘Why are you shouting at me, Diane?’

Fry took his arm. ‘Ben, sit down and shut up for a minute. Take a few deep breaths.’

He opened his mouth to speak, but she snarled at him, and he closed it again quickly. He sat down.

‘All right, that’s better,’ she said.

‘Can I speak yet?’

‘Just collect your thoughts first. I’m getting the impression you have something to tell me that you think is important. But so far you haven’t managed a word of sense. Not a word.’

‘Oh. Are you sure?’

‘There was somebody called Billy, and somebody called Dickie, and one of them was screaming. That’s all I got. The rest of it was gibberish.’

Cooper wiped a hand across his forehead. ‘I’d better start again.’

‘I’ll fetch you some water. And I suggest when you do start again, you start from the beginning.’