The Wire in the Blood. Val McDermid

about meeting a variety of needs – to dominate, to inflict pain, to provoke distinct responses, to achieve sexual release. The means can vary, but the end remains constant.’

      He took a deep breath and tried to keep his mind off the very particular variations he’d seen at first hand. ‘For a killer whose pleasure comes from inflicting pain and hearing victims scream, it’s immaterial whether he …’ his voice faltered as irresistible images climbed into his head. ‘Whether he …’ They were all looking at him now and he desperately struggled to look momentarily distracted rather than shipwrecked. ‘Whether he … ties them up and cuts them, or whether he …’

      ‘Whether he whips them with wire,’ Shaz said, her voice casual, her expression reassuring.

      ‘Exactly,’ Tony said, recovering fast. ‘Nice to see you’ve got such a tender imagination, Shaz.’

      ‘Typical woman, eh?’ Simon said with a grunt of laughter.

      Shaz looked faintly embarrassed. Before the joke could escalate, Tony continued. ‘So you might have two bodies whose physical conditions are very different. But when you examine the scenario, things have been done that were additional to the act of killing and the ultimate gratification has been the same. That’s your signature.’

      He paused, his control firmly in place again, and looked around, checking he was taking them all with him. One of the men looked dubious. ‘At its most simplistic,’ he said, ‘think about petty criminals. You’ve got a burglar who steals videos. That’s all he goes for, just videos, because he’s got a fence who gives him a good deal. He robs terraced houses, going in through the back yard. But then he reads in the local paper that the police are warning people about the video thief who comes in through the back yard, and they’re setting up neighbourhood watch teams to keep a special eye on back alleys. So he abandons his terraced houses and instead he goes for between-the-wars semis and gets in through the side windows in the downstairs hall. He’s changed his MO. But he still only nicks the videos. That’s his signature.’

      The doubter’s face cleared. Now he’d grasped it. Gratified, Tony picked up a stack of papers divided into six bundles. ‘So we have to learn to be inclusive when we’re considering the possibility of a serial offender. Think “linking through similarity”, rather than “discounting through difference”.’

      He stood up again and walked around among their work tables, gearing himself up to the crucial part of the session. ‘Some senior police officers and profilers have a hypothesis that’s more confidential than the secrets of the Masonic square,’ he said, capturing their attention again. ‘We believe there could be as many as half a dozen undetected serial killers who have been operating in Britain over the past ten years. Some could have claimed upwards of ten victims. Thanks to the motorway network and the historic reluctance of police forces to exchange information, nobody has sat down and made the crucial connections. Once we’re up and running, this will be something we’ll be considering as and when we have time and staff available to look at it.’ Raised eyebrows and muttering filled his momentary pause.

      ‘So what we’re doing here is a dummy run,’ Tony explained. ‘Thirty missing teenagers. They’re all real cases, culled from a dozen forces over the last seven years. You’ve got a week to examine the cases in your spare time. Then you’ll have the chance to present your own theories as to whether any of them have sufficient common factors to give us grounds for suspicion that they might be the work of a serial offender.’ He handed them each a bundle of photostats, giving them a few moments to flick through.

      ‘I should emphasize that this is merely an exercise,’ he cautioned them, walking back to his seat. ‘There’s no reason to suppose that any of these girls or lads has been abducted or killed. Some of them may well be dead now, but that’s probably got more to do with the attrition of life on the street than foul play. The common factor that links them is that none of these kids were regarded by their families as the kind who would run away. The families all claimed the missing teenagers were happy at home, there had been no serious arguments and there were no significant problems with school. Although one or two of them had some history of involvement with the police or social services, there weren’t any current difficulties at the time of the disappearances. However, none of the missing kids subsequently made contact with home. In spite of that, it’s likely that most of them made for London and the bright lights.’

      He took a deep breath and turned to face them. ‘But there could be another scenario lurking in there. If there is, it’ll be our job to find it.’

      Excitement started like a slow burn in Shaz’s gut, powerful enough to dim the memories of what she’d read about Tony’s last close encounter with a killer. This was her first chance. If there were undiscovered murder victims out there, she would find them. More than that, she would be their advocate. And their avenger.

      Criminals are often caught by accident. He knew that; he’d seen programmes about it on the TV. Dennis Nilsen, killer of fifteen homeless young men, found out because human flesh blocked the drains; Peter Sutcliffe, the Yorkshire Ripper, despatcher of thirteen women, nicked because he’d stolen a set of number plates to disguise his car; Ted Bundy, necrophiliac murderer of as many as forty young women, finally arrested for speeding past a police car at night with no lights. This knowledge didn’t frighten him, but it added an extra frisson to the adrenaline buzz that inevitably accompanied his fire-setting. His motives might be very different from theirs, but the risk was almost as great. The once soft leather driving gloves were always damp with his nervous sweat.

      Somewhere around one in the morning, he parked his car in a carefully chosen spot. He never left it on a residential street, understanding the insomnia of the elderly and the late-night revels of the young. Instead, he chose the car parks of DIY stores, the waste ground beside factories, the forecourts of garages closed for the night. Secondhand car pitches were best; nobody noticed an extra car there for an hour or two in the small hours.

      He never carried a holdall either, sensing it to be suspicious at that time of night. A policeman spotting him would have no cause to think he’d been out burgling. And even if a bored night-beat bobby fancied the diversion of getting him to turn out his pockets, there wouldn’t be much to arouse suspicion. A length of string, an old-fashioned cigarette lighter with a brass case, a packet of cigarettes with two or three missing, a dog-eared book of matches with a couple remaining, yesterday’s newspaper, a Swiss Army knife, a crumpled oil-stained handkerchief, a small but powerful torch. If that was grounds for arrest, the cells would be full every night.

      He walked the route he’d memorized, staying close to the walls as he moved silently down empty streets, his blank-soled bowling shoes making no sound. After a few minutes, he came to a narrow alley which led to the blind side of a small industrial estate he’d had his eye on for a while. It had originally been a ropeworks and consisted of a group of four turn-of-the-century brick buildings which had recently been converted to their present uses. An auto electrician’s sat next to an upholstery workshop, opposite a plumbing supplier and a bakery that made biscuits from a recipe allegedly as old as the York Mystery plays. He reckoned anyone who got away with charging such ridiculous prices for a poxy packet of gritty biscuits deserved to have their factory razed to the ground, but there wasn’t enough flammable material there for his needs.

      Tonight, the upholstery workshop was going to go up like a Roman candle.

      Later, he’d thrill to the sight of yellow and crimson flames thrusting their long spikes into the plumes of grey and brown smoke billowing up from the blazing cloth and the wooden floors and beams of the elderly building. But for now, he had to get inside.

      He’d made his preparations earlier that day, dropping a carrier bag into a rubbish bin by the side door of the workshop. Now he retrieved it and took out the sink plunger and the tube of superglue. He walked round the outside of the building until he was outside the toilet window, where he stuck the plunger to the window. He waited a few minutes to be certain the contact adhesive had hardened, then he gripped the plunger with both hands, braced himself and gave a sharp tug. The glass broke with a tiny tinkle, the fragments falling on the outside of the window, just as they would if it had exploded from