“CCTV camera,” said Banbury. “There was someone in the morgue corridor prior to the time period of Finch’s death. He was captured on the hard drive of the security system at Bayham Street. 1 need to check it out.”

“You’re not to leave this building unaccompanied,” said Longbright. “I have to come with you.”

“I’ll need Giles. We work as a team. We’ll achieve more.”

“Then bring him as well.” The young forensic scientist’s impetuosity might have angered Finch, but proved useful when a quick eye was required at crime scenes. He and Banbury fired ideas and hypotheses that could reach conclusions others missed.

“Getting a positive ID from a piece of blurry monochrome camera footage is going to be a challenge,” warned Banbury as the trio dodged slush and traffic in Camden High Street. “But it’ll give us the exact second he appeared, and that’s a start point.”

“Arthur says there’s an old lady who lives opposite the mortuary entrance. If we’re patient, she might get us a description.”

“If someone else managed to enter that room, there should be evidence of a forced entry, and the lights would have been on,” Kershaw was muttering. “Do you think the old lady can tell us that? And how do I really know if anything has been taken? Finch never showed anyone what he kept there. He certainly never catalogued it properly. None of his ledgers are up to date. He stored most of the important information in his mind. If someone was trying to get back at the unit, there are a lot of easier ways than breaking into a locked room and re-sealing it to appear as though it was never entered.”

“Mr. Bryant thinks we don’t need him to sort this out,” said Longbright, but she did not pass on everything Bryant had told her. Watch Kershaw, he’d said. The boy is clever but lacks understanding. He needs to develop his emotional responses.

She listened to Kershaw and Banbury arguing together as they headed into the Camden side streets, and wondered if it was possible that either of them could have caused the elderly pathologist’s death. Finch had been more frail than he pretended; it could have been an accident. At best, a lie. At worst, manslaughter or murder. The DS knew she could not afford to let either of them out of her sight.

Back at the unit, Mangeshkar and Bimsley had taken Bryant’s advice literally, and were seated across from each other, trying to solve the puzzle of the medical examiner’s death by themselves.

“We know how they think, sort of,” Colin told his fellow DC. “We should be able to make a positive contribution.

Apart from anything else, think how it would help our careers.“

“Bryant would start by looking for some kind of supernatural influence,” said Meera scornfully. “He probably thinks Finch was cursed by witches, or placed under an evil spell that made him punch himself in the heart.”

“He just uses the process as part of what he calls ”Open Thinking,“ Meera. You don’t suppose he really believes all that stuff.”

“I don’t? Then come and look at this.” She grabbed Colin’s sleeve-his hand would have provided too much contact- and led him to Bryant’s room. “Does this look like the headquarters of London’s most advanced crime think tank to you?”

She had a point; on the mantelpiece was Bryant’s chased-silver human skull, which had been smuggled out of Tibet by dissident monks and now oozed rank-smelling algae from its brainpan. Beside this, wax from a pair of wonky black candles belonging to a satanic cult had dripped over his copies of The East Anglia Witches: An Investigation Into the Nature of Evil, The 1645 Omens of the Apocalypse, Grow Your Own Hemp and The Beano Christmas Annual 1968. On the wall, a drawing of a fractal pentagram with a Scraperboard print of a goat’s head pinned at its centre was signed ‘To Arthur- Happy Winter Solstice, love, Maggie.“

“You knew his methods were weird when you were transferred here,” Bimsley reminded her. “You’ve also seen the results he gets.”

“Yeah, he almost got John’s granddaughter thrown off a roof, didn’t he? They managed to hush that one up. He may get results, but only by putting others at risk. I’ve been based with dodgy units before, but at least I knew what I was dealing with on the problem housing estates. I was thinking of transferring out of here anyway, before this happened. The whole idea has been a mistake. Everyone in the unit is infected with the same weird mind-set. I was taught structure, responsibility, a chain of command; instead I’m surrounded by anarchists and nutters.”

“You don’t really want to leave,” Bimsley told her.

“Really? You know that, do you?”

“You’re still holding my sleeve.” Bimsley grinned at her.

“At least it’s not your hand.”

“It is now.” He pressed his slender fingers into her palm.

“And you-you’re the worst of the lot!” She threw his hand aside as if it were a tarantula and stalked from the room.

“You’re just playing hard to get,” he called after her. “I won’t wait forever!”

Eleanor Newman’s room had been decorated by her husband in the late sixties, but he had died of a stroke just after laying the last piece of swirly amber carpet, and the place had never been touched again. Longbright felt completely at home in an apartment that resembled John Steed’s set from The Avengers. She had been sporting the bleached-blonde Ruth Ellis look for long enough now, and felt it was time to move forward a decade into the Emma era. As she sank back into a black leather Eames chair, Banbury showed Mrs. Newman footage of the mortuary corridor from the hard drive, loaded onto his MP3 player.

“Dear me, he looks like a drab grey duck,” said Mrs. Newman, rolling her wheelchair a little closer, “with the hoodie, the baseball cap and the baggy trackie bottoms, the universal dress code of the socially impoverished male. It’s not the lack of money, it’s the paucity of imagination I find so depressing.” Although her face was densely lined, she still had the bone structure of a model and the posture of a dancer. She examined the images with a keen and careful eye. “I miss less from this window than your cameras.”

“This is the footage shot from the far end of the corridor,” Banbury explained. “The lighting isn’t very good but you might be able to tell if this was the boy you saw. It’s like regular film footage, just on a little screen. Can you see?”

“Is there any particular reason why you’re addressing me as if I’m a five-year-old? I was a camerawoman at Pinewood Studios for thirty years, young man. I may be old, but I probably have a better visual grasp than you. The only difference is that I can afford more memory than this piece of rubbish. Won’t they at least buy you a sixty-gig iPod?” She gave the plastic screen a desultory flick with her nail. Kershaw suppressed a laugh as he caught Banbury’s disgruntled glare. “I wasn’t at the window when this boy entered the building. The nurse must have been running my bath. No details on his face, but he’s got rather a nice bum. It’s not the equipment you need to concentrate on; it’s the lighting. You say you work for Arthur?”

“That’s right, ma’am.”

“I met him in 1968, you know. What a year of riots and revolutions; it felt as if we were on the brink of a reborn world, a wonderful time to be young and idealistic. I tried to get him to go out with me. I suppose that was before either of you was born. Wait, run that back. Any chance of you enlarging the image without it pixelating too much?” She felt for a pair of glasses on her side table and fixed them to her nose. “The badge on his sweatshirt, I recognise it. Camley Road Canoe Club. It’s a ten-minute walk from here along the canal.

Funded by Camden Council to keep problem kids off the streets. Upload the shot onto my computer and I’ll print you off a screen-grab.“

She indicated the mock-Gothic cupboard behind her. Banbury opened it and found himself looking at twenty grand’s worth of state-of-the-art kit. “I can’t get out to the world anymore,” Mrs. Newman explained, “so now the world comes to me.”

The Camley Road Canoe Club was a trapezoid of stained concrete perched over the edge of the Regent’s Canal. It was surrounded by an estate of neat redbrick dolls’ houses with fake lead-light windows and white plastic drainpipes, the architectural equivalent of an Essex girls’ hen night. The clubhouse appeared to be shut, but a bored-looking girl with hoop earrings and a dangling fag divorced herself from two male friends and buzzed them in when she saw that they weren’t about to go away. “It’s shut,” she told them. “Ain’t open ‘til the weekend.”

“Why’s that?” asked Longbright, who had already noticed that she was wearing the badged club sweatshirt.

The girl studied the sergeant’s perfectly coiffured Ruth Ellis hair in amazement. “Shuts early in the afternoons. Council cutbacks, innit.”

“Do you work here?”

“Why?” The girl grouped herself defensively against the youths at her back.

“We’re looking for this lad. Wondered if he’d been in recently.”

“Don’t know him.” The girl spat smoke, barely bothering to look. One of her friends, a skinny Indian boy with spiked hair and the posture of a boomerang, peered over her shoulder. “That’s Dizzee,” he said firmly. “He don’t come here no more. Got kicked out, innit.”

“Shut up, Pravin,” the girl snapped, clearly not happy about sharing her knowledge with strangers.

“But he was a member of the club.”

“Yeah.” A grudging admittance as she examined the end of her cigarette.

“Then they’ll have a record of his address here.” Banbury headed for the reception computer, addressing the Indian boy, who obviously wanted no trouble. “What’s Dizzee’s real name? Dylan?”

“Mills,” said the boy. “Owen Mills.”

“Dylan Mills is the real name of the hip-hop singer Dizzee Rascal,” Banbury explained to the mystified Longbright. “This kid is smart enough to wear a hood, but dumb enough to wear a badge.” He seated himself behind the reception desk and typed for a minute. “Here you go, one-oh-five Disraeli House, that’s on the Crowndale Estate. Call it in.”

Forty-five minutes later, a very nervous Owen Mills found himself sitting in the interview room at the Peculiar Crimes Unit.

“Welcome to the PCU,” said Longbright, offering a hospitable smile. “How would you like to help us solve a crime?”