‘Exactly,’ said Cooper. ‘You know that, and I know that. And anyone who’s ever requested film from it must know that, too.’

Hitchens got up to escort Dr Kane out of the building, leaving Diane Fry on her own. She watched them walking away down the corridor, the DI’s hand lightly touching the doctor’s elbow as he chatted to her about his student days in Sheffield.

Fry knew that seeing visitors off the premises would normally be a job the DI delegated to somebody more junior. But for Dr Kane, Hitchens was making an exception. Probably because she was an expert and had to be treated with respect. Probably.

To prevent herself from thinking about it any more, Fry lowered her gaze and found herself staring at the yellow highlighter marks on the transcript in front of her. She wished she hadn’t used yellow. Now that the colour had dried, it looked faintly rancid and unhealthy, like a four-day-old bruise or a urine stain. Pink or orange would have been much more cheerful.

But who was she kidding? Whatever colour she chose wouldn’t make a bit of difference to the sly, evil look of the words themselves.

I can smell it right now, can’t you? It’s so powerful, so sweet. So irresistible.

She left the DI’s office and walked slowly back to the CID room. Ben Cooper wasn’t at his desk, but Gavin Murfin and a couple of other DCs were in, and they looked up as she entered.

As usual, there was a whiff of pastry from Murfin’s direction. Steak pie or Cornish pasty, she wasn’t sure. Right now, she wouldn’t have been able to identify it. Another, more elusive smell was in her nostrils, something rancid, unhealthy, yellow and evil. It was a smell she knew would only get closer and couldn’t be dispersed by the ventilation system.

I can smell it right now, can’t you? … It’s the scent of death.

‘Let’s get the map out,’ said Hitchens, almost before he could get back into the CID room. ‘We need the Ordnance Survey map, Diane – White Peak.’

‘We could use the mapping system on the computer,’ said Fry.

‘That’s no good for a six-mile radius. We won’t be able to see enough detail at that scale.’

He cleared a table while Fry found a copy of the right map and they spread it out.

‘Wardlow is here,’ said Hitchens. ‘Now we need a ruler to measure three miles in each direction. Damn it, the village is too close to the edge of the map – we’ll have to turn over to the other side. Why is everything you want to look at on an OS map always too close to the edge?’

Cooper came in as they were finding a ruler, and Hitchens called him. ‘Ben, just the lad we need. You know this area, I’m sure.’

‘Yes, sir. What is it you’re looking for?’

The DI explained, while Fry checked the scale of the map and used the ruler and a pen to draw a rough circle around the location of the public phone box in Wardlow, helpfully marked by the OS with a capital ‘T’ and a little blue handset.