‘Before you ask, there wasn’t anyone else in here. Did you think the lady might have come in the aquarium to meet someone?’

‘It was a possibility. Was she carrying anything when she came in?’

‘Come to think of it, yes. A carrier bag of some kind.’

‘And did she still have the bag when she went out?’

‘I can’t recall.’

In another hologram, Cooper watched an elephant turn into a pig, then a hippopotamus. Further along the wall, a man metamorphosed into a werewolf, and Dr Jekyll became Mr Hyde. Piped music played in the background, something soothing and a bit New Agey. But it was interrupted by noises from the amusement arcade downstairs: the rattle of coins, the blaring music of the video games. Real life intruded, even into a room full of illusions.

‘And that was it?’

‘Yes, that was it. Then she left.’

‘Back down the stairs?’

‘You have to exit through the amusements, but she didn’t stop in there. She was in a hurry to get out by then.’

‘When she got out on to the street, which way did she go?’

‘I couldn’t tell you.’

‘All right. Did you notice anything unusual about her manner?’

‘No. I got the impression she was killing time. In fact, I’d have said she came in to get out of the rain – except it wasn’t raining that day.’

‘How was she dressed?’

‘Oh, I dunno. A jacket of some kind. Not a coat … Like I said, it wasn’t raining, or even particularly cold.’

‘Colour?’

‘Black, I think. And slacks – trousers, you know, not jeans. She wasn’t scruffy.’

‘Oh? Did you get the impression she’d dressed up a bit to come out?’

‘Well, she’d made an effort, definitely.’

‘But not to come here? She was just killing time, right?’

‘She wasn’t looking for anyone in here, I don’t think. She hardly seemed to notice other people, except the children. She looked like a self-contained sort of person. Do you know what I mean?’

‘Yes, I know what you mean. Thank you for your time.’

As he left, Cooper noticed that a view from the camera in the thermal bath was projected on to a screen over the entrance. On a busier day, you could watch from the street as children fed the fish or threw their coins into the water, hoping for good luck.

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.

‘A well-nourished Caucasian female, physical condition consistent with a stated age of twenty-nine. Sixty-one kilos, one hundred and seventy-three centimetres.’ The pathologist looked up. ‘That’s about nine stone nine pounds, five feet seven inches.’

‘Thank you.’

‘Physical injuries are all superficial. No signs of external trauma.’

‘Any signs of recent sexual activity?’ asked Fry, to take her mind off the smells.

Mrs van Doon pursed her lips and flicked back her sleeves. ‘You have all the best ideas, don’t you?’

‘I need any indication I can get of whether there was another person in the house that night.’

‘Yes, I understand where you’re heading. I can see why they employ you on these cases. I imagine you don’t leave any bit of dirt unexamined.’

‘We have a lot in common, then,’ said Fry coolly, surprised by the sharpness of her tone. But she supposed even pathologists were human sometimes.

‘No, no signs of sexual intercourse. This is the only item that’s of real interest –’

The pathologist held up a body part that had been cut free and sliced open with a scalpel. Fry didn’t recognize it, which was probably what Mrs van Doon expected.

‘This is the oesophagus. The black stains you can see on the inside are soot. They suggest that your victim was alive when the fire started, because she breathed in smoke. There’s enough in the oesophagus to have resulted in asphyxiation.’

‘So that’s the cause of death?’

‘Possibly … There’s a sort of triple whammy in these cases. Inhalation of soot particles damages the airways, because the particles are super-heated and contain toxic agents. Hot air burns the upper passages, too, and can cause vagal inhibition. But there’s a third factor. Carbon monoxide is normally associated with soot inhalation, and I can deduce some CO poisoning from the cherry pink discoloration on the torso. We’ll get blood samples analysed for carboxyhaemoglobin levels. But anything above fifty per cent is fatal.’

‘I presume there’ll be a report soon.’

‘When I get time.’ The pathologist began to strip off her gloves. ‘The other two fire fatalities are children, I see.’

‘Yes.’

‘You know, the children look almost undamaged, but for the carbon monoxide discoloration and some smoke staining.’

Fry searched for something to say. ‘That makes it worse, I suppose. They don’t look as though they should be dead, do they?’

‘On an emotional level, that’s true.’

She watched the pathologist drop her gloves into a bin, wondering if she’d just been the object of a subtle insult, or a slur on her professionalism. On an emotional level? But perhaps it had been a moment of personal confession. It was difficult to tell with Juliana van Doon.

13

In Matlock Bath, houses seemed to climb on top of each other in their haste to escape the valley floor. Above them were the two Victorian pleasure grounds on Masson Hill – the Heights of Jacob, the Heights of Abraham. Their biblical slopes were occupied by modern leisure parks now, the fairy-tale shapes of castles and towers poking up among the trees.