In fact, if he’d been standing here at the right time on Saturday afternoon, he would probably have seen Rose Shepherd. Cooper imagined a ghostly likeness of her now, superimposed on the tiles. For a second, Miss Shepherd really seemed to be standing at the edge of the pool in her black jacket, clutching her carrier bag. But the moment he moved his head, she disappeared again, vanishing like an image in one of those holograms. And she’d given him no sign – no clue at all why she’d come here on Saturday, all dressed up for an afternoon out in Matlock Bath.

There wasn’t much chance to talk at a Home Office post-mortem. There were always too many people present – the SIO, crime-scene examiner, photographer, pathologist and her assistant. And without the distraction of conversation, Fry found it difficult not to think about the smell.

She had no problem with the sights, or with being passed unidentifiable, bloody items for packaging now and then. She wasn’t even bothered by the pathologist eating a snack during the proceedings, as some of them did. But the smell was something else.

Some old hands suggested putting Vicks VapoRub up your nose before attending a PM. Others pointed out that Vicks was designed for clearing the nose, so it actually heightened your sense of smell, instead of masking odours. Two extra strong mints might help, though, they said. Fry hadn’t found anything that worked.

‘In the absence of any other priorities, I’ve scheduled them in the order they came in,’ said the pathologist, Juliana van Doon. ‘So it’s fire victims first. But since there are three of them, I’ve requested a colleague to come in and assist me. So we shouldn’t be too long getting to your shooting.’

‘That one isn’t mine. I’m on the house fire.’

‘Oh, I thought you’d been promoted.’

Everyone in the autopsy suite was fully suited and booted to avoid infection. The suits were also supposed to prevent your clothes from trapping the smell, so that members of the public and their dogs didn’t shy away from you and throw up when you went out on to the street.

It was Lindsay Mullen who lay on the dissection table. The mark of the incision where the pathologist had opened her up glared a startling red against her waxy skin. Fry was glad she hadn’t witnessed the removal of the skull for examination of the brain. The noise of the saw and the smell of singed bone were the worst part of a postmortem for her. Well, there was one other stage that was as bad – the moment when the loosened scalp was folded forward over the corpse’s face with the skin inside out, like a towel thrown over the beer pumps at closing time.