‘All right. Then we have to follow the signs at “the gibbet and the rock”. Let me make a few phone calls, and we’ll go.’

‘Are you sure of this? There could be other interpretations.’

Fry glanced at him as she picked up the phone. ‘Yes, I’m sure. I’m starting to get inside his head here, Ben. Isn’t that what you said we should be able to do? Well, I’m doing it.’

‘The DI said no more chasing around the countryside –’

But she was already speaking to someone on the phone. Cooper looked at the urn on his desk and the missing persons files. Oh, well. For once, he couldn’t be accused of going off and doing his own thing. It was Fry’s decision.

And she might be right. He hadn’t learned the messages by heart the way she had, but Cooper could recall the one line Fry had missed quoting from the second call. You can see it for yourself. You can witness the last moments. They might not have a lot of time to waste.

Half an hour later, Cooper found himself driving back towards Wardlow. It was Matt who’d reminded him that the road between Wardlow and Monsal Head had a local name – Scratter. ‘Scrat’ was a dialect word for scratching or clawing, and horses had to ‘scrat’ up the hill. But some said the name came from skratti, the Scandinavian word for a demon. The Devil himself was called Old Scratch in local folk stories.

The Vikings had left quite a legacy in these parts. Derbyshire had once belonged to Denmark, with an invading army stationed in the next county, in the caves under Nottingham Castle. Those Vikings had been superstitious folk, and had peopled the landscape with demons and monsters, entire swarms of them lurking in every dark place and at every unfamiliar spot on the map.

Over the centuries, their descendants had been reluctant to give up the most sinister stories, even in the face of all that new-fangled religion and rationality. Some of those legends had taken such a powerful grip on the hills and shadowed valleys that they would never be dislodged. Demons hid in the very place names.

‘Ben, this Professor Robertson,’ said Fry as they drove through Wardlow. ‘He’s definitely weird, isn’t he?’

‘He’s all right. He’s just a bit …’ Cooper hesitated, struggling for the right word. ‘Well, perhaps a bit obsessive. Look, he has this specialized interest, a subject he thinks he’s the world greatest expert on. He loves showing off his knowledge. That makes him appear rather …’

‘Weird?’

‘Just because he’s slightly eccentric and obsessed with the rituals of death doesn’t mean he goes home every night and acts out necrophiliac fantasies on the bodies of his victims.’

‘Has he talked to you about necrophilia?’

‘No.’

‘So that one came from your own imagination, did it?’