Preparing a body for viewing, the embalmer moulded a face, much like the forensic artist had done to create the impression of Audrey Steele. Dead faces dropped and looked grim, so they had to be pushed into an appropriate shape to please the relatives. Tweak the mouth, brush the hair, apply cosmetics.

Drained, stuffed and painted. That’s what Professor Robertson had said. Well, forget the draining and stuffing. A man who could make the dead look alive would surely be able to disguise his own appearance with cosmetics, at least well enough to fool a casual observer. A whole range of liquids, creams and powders had been in stock at Hudson and Slack. A practised hand could easily change colouring, widen or narrow the cheeks, conceal a double chin, firm up the eyelids.

Then Cooper remembered what Madeleine Chadwick had said about the man who’d turned up wanting to see the bones in the Alder Hall crypt, the man whose age she’d been so vague about. Mrs Chadwick ought to have been able to identify his smell. But it had been out of context, a scent that she wouldn’t have expected to notice on a man. She’d have associated it more with a session at the beauty parlour, perhaps. It might have been the blend of alcohol, oil, wax and glycerin that came from cosmetic creams and massage oils.

Cooper waited until Nick Summers was free, and went back to the counter. ‘Environment and Ecology?’ he said. ‘I don’t suppose you happen to know a plant that looks like ten-foot-high cow parsley with a purple stem?’

When he got back to his flat, Cooper checked his answering machine again, then turned on his PC and did a Google search to see whether Nick Summers’ suggestion was a good one. Yes, it certainly appeared to be the plant he’d seen. Giant hogweed. A nasty-looking thing, too.

The cheeseburger he’d eaten was stirring a bit in his stomach when he switched to one of the major online booksellers and looked up Beatrix Potter’s The Tale of Mr Tod. So ‘Tod’ meant death in German, did it? No doubt Professor Robertson would have been able to tell him that, if he’d asked. He probably knew the word for death in thirty-five languages.

But when the cover of the book came up on his screen, Cooper stared at it for a second or two, then slapped himself hard on the forehead.

‘What an idiot,’ he said. ‘That’s what you get for trying to be too bloody clever.’

The cover showed a classic Beatrix Potter illustration – a fox wearing a long scarf and a poacher’s jacket, climbing a stile over a stone wall.

‘Wait until I tell Diane in the morning.’

In the absence of anyone else, Cooper looked round for the cat to share his revelation with. ‘The German for death, indeed. Of course, it wouldn’t mean anything. But this …’

He stopped, looked at the screen again, and remembered the call he’d tried to make to Freddy Robertson. The professor wasn’t at home tonight.