“Just as well we don’t have to do anything except wait for the emergency services to come and dig us out, then,” said May. “I suppose I might try one of your boiled sweets.”

“You won’t like it,” Bryant warned, watching as his partner popped it in his mouth and pulled a face.

“What flavour is that meant to be?” May asked, tentatively moving his tongue about.

“It’s either gooseberry or Bovril. They’ve been in the same bag for the last five hours, so they probably taste of both. Put me out of my misery and call Janice, would you?”

May speed-dialled the number and spoke to the sergeant. “Your hunch with the old lady paid off, Arthur,” he said, after listening to her report. “They’ve found their witness. A seventeen-year-old West Indian kid called Owen Mills. They’re interviewing him now.”

“What time was he sighted leaving the morgue corridor?” asked Bryant.

“Hang on. Janice, Arthur wants to know what time the boy was seen exiting from the corridor-nine-oh-five A.M.”

“So unless Giles’s estimated timings are off, he didn’t kill Oswald. How did he get inside?”

“Arthur wants to know how he got in,” May asked, then turned to his partner. “He just pressed the buzzer.”

“That means Finch admitted him. I wonder why he would have done that. Can you ask her-‘

“God, you ask her,” said May, thrusting the mobile at him. “I can’t keep relaying the conversation.”

“Janice, the boy wasn’t just loitering; he went there with a specific purpose. Ask him what it was. Act like you know why; you’re just seeking confirmation. No, I’ll wait.” He rattled the sweet bag at May. “Want another one?”

“No, thank you.” He spat the brown-and-purple drop into a tissue.

Bryant returned to the phone. “Just passing by? Well, he’s lying. He’d seen someone punch that code and repeated the action to speak to Oswald, who would never have let him in without a very good reason, so the lad must have thought about what he was going to say. Keep trying, I need to talk to John for a mo.” He turned to May. “What’s the one thing that was different about the morgue this morning?” he asked.

“There was a fresh cadaver in it,” said May as an idea dawned.

“Precisely. I’m betting Mills knew the deceased, which was why he went to the morgue: to see the body. Why won’t he admit it? Because she was found dead in a shop doorway, and he’s frightened of being implicated.”

“So he probably knows she died of an overdose, and that means he might even be the one who supplied or administered it.”

“Possible, but not quite what I’m thinking. If he suspected he’d killed her, he’d be reluctant to walk into a Metropolitan Police compound. Janice: Renfield’s overdose case, you need to quiz Mills about his possible relationship with the girl. He may be able to confirm an ID. Okay, I’ll call you back.”

Bryant replaced the mobile in its dashboard cradle and briskly rubbed his hands together. “I think perhaps this could work, crime investigation by remote control. I could do this from the comfort of my armchair at home and never have to visit any more crime scenes. It would be interesting if the boy’s appearance at the morgue had some direct influence on Oswald’s death, wouldn’t it? It might mean the dead girl held a secret worth killing for.”

He picked up the mobile once more and redialled. “Janice, I know you don’t want to let the others out of your sight, but I think it’s important that Dan and Giles work together at Bayham Street. I think they’ve missed something. Yes, I do have an idea but I’m not going to tell you what it is, because this is your chance to prove yourselves. Get them to call me back.” He grinned at May. “We’ll have this whole thing sorted before Princess Poison sticks her royal nose around the door, trust me.”

May knew it was the worst possible declaration Bryant could make, because in his experience, a remark such as this usually heralded the arrival of the moment when everything started to go horribly wrong.

“I don’t know what we’re looking for,” said Banbury, flicking on the tic-inducing neon overhead. “God, it’s freezing in here.”

“Oswald never turned up the heating because of the bodies, although he was supposed to keep the place at eighteen degrees centigrade,” said Kershaw, pulling on plastic gloves. “He completed his training prior to public refrigeration. Everyone revered him as the perfect medical examiner, but he had his peculiarities, just like everyone else. And I can’t tell if the thermostat was raised this morning, so we have no exact time of death yet.”

“Stay within the markers.” Banbury pointed at the pathway of yellow tags he had attached between the doorway and the steel dissection table.

“If I do that, I won’t find anything new. If there’s something to be seen, it’ll be found at closer quarters. Bryant was eager to release us. He knows there’s more to this than meets the casual eye.”

“How can he? He’s stuck in a snowdrift four hundred miles away.”

“They were old friends, despite all those tricks he played on Oswald. He knows what he was likely to do or not do.” Kershaw carefully unlocked the medical cabinets that ran along the rear of the converted gymnasium. “It looks like we do have something missing here. MEs are required to list everything they keep on their shelves. I thought you checked them.” He pointed to a laminated card placed in a pocket of the door. “According to the register there’s supposed to be a bottle of naltrexone in this space.”

“What’s that?”

“It’s a type of naloxone, an opioid antagonist. It’s a fast-acting drug used to reverse the effect of strong narcotics like heroin and morphine. Addicts often have it as part of their emergency kit. And it’s not here, which means Finch must have used it recently. Don’t touch the hazard bins, they’ll contain sharps. Let me do it.”

He rooted about in the yellow plastic bin-liner for a few minutes, but turned up nothing. Pulling open the body drawer where he had stored the medical examiner, he bent over Finch with a halogen torch.

Banbury wasn’t keen on watching his partner study the corpse of a coworker, and kept his distance beyond the end of the drawer. He was more comfortable examining the circumstances of crime; dead faces bothered him. “What are you looking for?” he asked.

“Needle marks. It occurs to me that Finch might have been a user.”

“You think he was a drug addict?”

“No, but we know he suffered from heart disease and plenty of other age-related illnesses. He was a very private man. If he was in pain, he might have covered up the fact and taken something to quell it, like morphine. It’s the kind of traditional opiate that would have appealed to him. You take it in tablet form as well. Cancer patients can ingest it as a syrup. It would have made him lethargic, though, and I haven’t heard any reports of unusual behaviour on his part. If he’d accidentally overdosed, he would have had reason to use the naltrexone.”

“I thought you already checked his body.”

“I only had time to carry out a preliminary survey before I was accused of murder by the unit’s resident Diana Dors. Besides, Finch’s skin tone was naturally jaundiced, and I had no reason to look for opiates.”

“We haven’t got much in the way of prints,” said Banbury, disappointed. “I think Finch was in the habit of frequently cleaning the surfaces with sterile wipes.”

“What about the floor?”

“Sprung wood flooring sealed under a polymer-I might get something more from the carpet tiles, or in the corridor. By the time visitors reached here, their shoes were clean.” His mobile suddenly played the first seven bars of the overture to Utopia, Limited. ‘Sorry,“ Banbury apologised. ”I lent it to Mr. Bryant and it came back playing Gilbert and Sullivan. Hello?“ He listened for a moment. ”I don’t know. Hang on. Giles, the body of the unidentified girl-where are her clothes?“