‘What’s that?’ Perry asked.

‘It’s a dye from some security product,’ Summers said. ‘Probably pepper spray.’

Gillard nodded. ‘Beatrice’s friends said she had a pepper spray. Most of them have a permanent dye, but some of the better ones have a UV marker. They’re generally illegal in the UK, but it’s further evidence that she fought like crazy to save herself, and even had the time to use the spray. With luck the perpetrator will be similarly marked.’

‘Was she sexually assaulted?’ Perry asked.

‘I was going to come to that,’ Summers said. ‘There are scratches to the vulva, and traces of bleach internally, which indicates to me she may have been washed post-mortem, even before the immersion in the river.’

Gillard blew a sigh. ‘That tells us the perpetrator is not only a sexual predator but a calm one. He has somewhere to work on the body before deciding how to dispose of it. It just reinforces the notion that this is a man who is comfortable with the dead. A first-time murderer often panics, and just wants to get rid of the corpse as soon as possible. We already know that this man is in a different league. Forensically highly aware too.’

‘Ex-police?’ asked Perry.

‘It’s certainly possible,’ Gillard said.

‘There is one final thing,’ Summers said. ‘A particular question about the time of death has been puzzling me. I understand that the victim went missing on Sunday. However the decomposition profile of the corpse is rather strange. The internal organs and digestive tract would normally decompose first, but they are in almost perfect condition. No discolouration of the abdomen at all. That of itself would indicate that she was alive until shortly before immersion.’

‘So the abductor kept her alive?’ Perry asked.

‘That’s possible,’ Summers said. ‘But I favour a different answer, given what we already know about Jane Morris. I think she too was frozen, for a couple of days at least.’

Perry’s eyes widened. ‘One frozen for almost forty years and one for a couple of days.’

Gillard nodded. ‘If our murderer has those kind of facilities, there could be many more victims. He has solved the biggest problem that most killers face: how to dispose of the body.’

Gillard sat in the hospital car park for half an hour, waiting for Perry to finish being sick in the toilet. He passed the time by listening to the Lysander Quartet CD. When you take apart a person to their constituent components, as Dr Summers had done, where does all that music, all that creativity, all that emotion end up? The bone, the gristle, Beatrice’s beautifully moulded flesh, were merely an extraordinary piece of scaffolding for the woman’s achievement, a rocket launcher for her destiny. The violin. To be able to communicate such extraordinary emotion through the judicious scraping of horsehair over wire. It was a wonder of the world. One now lost.

He looked up to see the detective inspector lurching towards him across the car park, wan face above a dark grey raincoat, hunched against the chill wind. He still didn’t look too chipper. Gillard quickly ejected the CD, and slid it carefully into its cardboard sleeve.