She had expected to find Finch in his usual spot, seated on a bentwood chair beside one of the sinks, reading a gardening magazine. He was now past the age when he could spend much of his day standing. She looked about, puzzled. “I don’t understand. Where is he?”

“Look under the sink,” Kershaw instructed her. Longbright slowly bent over, apprehensive of what she might find. Finch was lying on his back with his papery eyelids shut, his bony death’s-head face finally suited to circumstance. He looked for all the world as if he had decided to take a nap on the floor and then simply drifted beyond the vale of sorrow.

“Seems entirely at peace, doesn’t he?” Kershaw voiced her thought. “At a guess, I’d say he’s been dead for at least an hour. The exact time might prove difficult to pin down, but I’ll get to that problem later. There’s no blood, no outward sign of the cause. The only anomaly I can see is the angled bruise on the left side of his neck, about two inches long, just above his collar.”

Longbright crouched beside the pathologist’s body and gently touched her hand against his skin. “Looks new. What do you think it is?”

“I don’t know. I came here looking for Dan and found this instead. He’s cold to the touch. There’s a contusion on the back of his head, presumably caused by the fall. Ought we to call someone?”

“I’m not sure if he has any surviving relatives left in this country. His wife and son went home to Poland.”

“I’d heard he was depressed. John told me he’d changed his mind about leaving the unit, but Raymond Land wouldn’t take back his resignation. There’s a clear handprint on the stainless steel counter, Finch’s own I’d guess, because there’s a band missing on his fourth finger, where he wears a ring. It would be consistent with him placing his left-hand palm down on the surface. It’s the sort of thing you’d do to steady yourself. My first thought was heart attack, but what about suicide?”

“Surely a sudden illness is the most likely explanation,” said Longbright.

“Of course, that’s the first thing Dan will be considering after his examination of the room. The door was locked from the inside, and the only key in the room should be on the hook behind Finch’s desk, except it’s not. The windows require a pole to be opened, and have no external fastenings.”

“There’s another way into the mortuary,” said Longbright, looking up. “The ventilator shaft.”

“Right, the cover’s missing from the front of the extractor fan.”

“The pipe measures about forty-five centimetres,” said Dan Banbury, walking in beside them. “So unless someone trained a monkey to come and attack him I think we can rule out that possibility.”

“Murders in the Rue Morgue,” said Longbright. “How on earth do you know what the pipe measures?”

“You learn to make accurate measurements from sight-readings in this job,” said Banbury casually. “My wife’s a district nurse. She does the same thing when she’s pouring me a beer, measures it out to the centilitre. Look further under the table.”

“What is that?” Longbright spotted the grey metal object, a double-ended aluminium blade.

“He’d been complaining for weeks that no-one had come to replace the extractor cover.” Banbury pointed to the ceiling, and the framed end of the ventilation pipe. “Looks to me like the fan blade worked itself loose and finally came off, falling down and striking him on the neck.”

“A bit unlikely, don’t you think?” said Kershaw.

“You wouldn’t believe the stats on accidents in the workplace. Employees have more than one point six million a year in Britain alone, impaling themselves on pens, getting electrocuted by ungrounded metal toilets, falling out of windows, choking on paper clips. University College Hospital had a Woman last week who had managed to cut her throat opening a padded envelope. There’s no sign of a forced entry, and this is a secure building. Even so, Finch had the door lock changed last month so that it could only be opened from the outside with a key. Apparently he was fed up with Mr. Bryant wandering in and being rude to him all the time.”

“I don’t think he could face retirement in Hastings,” said Kershaw.

“This is not suicide, Giles. He was strange, I’ll admit, but he’d have to have been pretty bloody perverse to loosen the blade of an extractor fan and stand underneath it with his neck exposed, waiting for it to fall off. Besides, there’s nothing to stand on in here. He’d never have been able to reach it in the first place.”

“I’m talking about finding some kind of malignant chemical in his body. Finch had a background in biology and chemistry. If he had really wanted to commit suicide, he’d have been able to access any amount of painless drugs for the purpose.”

“I know Arthur has always encouraged us to rank the most bizarre possibilities beside more obvious causes of death,” said Longbright, “but isn’t this going a bit far? Even if he did found the PCU upon that idea.” She studied the prone pathologist with sadness. “Poor Oswald, he never did get to leave this place.”

Longbright rose and checked around the room. She couldn’t smell alcohol on the body, and Finch had no history of drink or drug abuse. Clear-headed suicides usually tidied up before killing themselves. The pathologist’s casebook and notes were scattered over the workbench. True, he had tried to rescind his resignation, and was probably mortified about his failure to do so, but depression was his natural state.

She wondered whether to tell her bosses and have them return to the unit, but decided against it. She understood their thought processes better than anyone, and could partially reproduce them if necessary. It was time for her to become more independent.

“What would John do next, do you think? Set up a common approach path, run a particle sweep, start swabbing for DNA?”

“The trouble is, neither he nor Bryant ever operated in the prescribed official manner,” said Banbury. “Their methodology is as unpredictable as a wind before a storm.”

Longbright pinched a glossy crimson lip and studied the scene, trying to clear her head of preconceptions. Finch had been standing at his workbench, and had fallen onto his back. He was left-handed. If the fan had spun off and fallen on him, wouldn’t he have heard the sound of it coming loose? What had absorbed his concentration so intently? She looked at the workbench and saw loose papers, an uncapped ballpoint pen, notebooks, a broken-backed toxicology manual, nothing out of the ordinary.

“What’s the first thing you do if you hear a noise above you?” she asked Banbury. “You look up.”

“Helicopters,” said Banbury enigmatically. “That’s what we used to call those seeds with little wings that fell from trees when we were nippers. They don’t fall straight down, do they? The fan blade wouldn’t, either. It’s lightweight aluminium. Finch looked up, stretching his neck, and it could have come down at him from an angle, striking a blow from the side.”

“What, you think the blow to his neck caused a blood clot, some kind of internal haemorrhage? That seems no more likely than the idea of him killing himself.”

“I’m not going to perform an autopsy on him, Janice,” stated Kershaw. “Not only would it be unethical, the idea of using Finch’s own medical instruments to divine the cause of his death would be highly inappropriate. We’d have to falsify the paperwork.”

“See, that’s the difference between you and Oswald. He would never show such squeamishness when it’s a matter of doing the right thing.”

“I’m not squeamish.” Kershaw bridled. “It’s a moral issue.”

The detective sergeant was not one to see the world in shades of grey. “You knew about the unit’s habit of ignoring the boundaries of propriety before you came to us,” she warned him. “If you want to prove yourself a worthy successor to Oswald, this is where you start.”