knobbin'?"' She smiled pityingly at him. 'Good plan: I can see that working.'

Logan scowled at her. 'If you 'II let me finish. We get a couple of WPCs done up as bait and they do the rounds. If someone tries to take them anywhere we've got them wired for sound: the unmarked cars follow and we catch the guy in the act.

What do you think?'

Steel wrinkled her nose and took a good look at Logan's crude diagram. 'Don't think it stands a chance in hell, but what have we got to lose?' she said at last. 'Go pick yourself out a couple of WPCs. Remember, this bloke did Rosie Williams and Michelle Wood so he can't be all that fussy. I want a couple of pugglers.' Logan said he'd see what he could do.

It was the perfect day for drying towels: sun shining, light breeze and no midges. Ailsa smiled, taking pleasure from the simple domesticity of it all. Gavin had promised to come home from work on time for a change. So tonight was going to be special: she was still ovulating after all.

She pulled the last towel from the basket and pegged it up on the line. All done. And then she caught the tell-tale, clinging stench of cigarette smoke, drifting through the fence from next door's garden. It was the pointy-faced boyfriend, his features bruised and battered. Again. Why he stayed with that horrible, drunken, abusive, violent woman Ailsa just couldn't understand. Surely any sane man would have left her the first time she broke his nose. Or the second. Or third…

The boyfriend was smoking with his head back against the metal whirly washing thing. Wincing as he breathed out, one hand flinching over his ribs, unaware that Ailsa was watching him. He finished his cigarette and flicked the butt out into the knee-deep grass where it disappeared among the weeds.

A loud shout from inside the house and the boyfriend jumped. In that moment his eyes caught Ailsa's and she knew he was every bit as trapped by this horrible harridan as she and Gavin were. She was like a mincing machine for the soul, grinding them up until nothing was left but a bloody pulp. Shoulders slumped in defeat, the boyfriend turned and limped into the house.

Ailsa watched him go with a shudder. There, but for the grace of God…

While the inspector was off on yet another extended fag break, Logan trolled through Michelle Wood's post mortem report. The killer had managed to snap one of her legs, both arms, and almost all of her ribs. Internal organs ruptured, probably caused by her attacker stamping on her stomach. Head battered repeatedly with fists, feet, a rock … Someone had really gone to town on her. Logan sighed, looking at a crime scene photograph: a big, full-colour eightby-ten glossy of Michelle's plastic-bag-smothered head.

There was no doubt about it: their boy was getting better at it. Every attack worse than the last, until…

Logan swore. How the hell could he have missed it? He shouted for DC Rennie. 'Grab your notebook: I want you to find out who patrols the docks, someone who knows the layout and the girls, we-'

'Excuse me, sir?' It was PC Steve. He hung his head round the door and smiled uncertainly in Logan's direction. 'DI Insch wants to see you.'

Logan groaned, wondering what he'd done wrong now.

'OK,' he told Rennie, 'you go: get me a name. I want to speak to them.' Then he remembered the Aberdonian pimp and the Lithuanian teenager. 'And show those identikit pictures round again – someone must know who they are.'

There was a new corkboard on the wall of DI Insch's incident room, divided up into six sections – each square taken up by a name, a face and a post mortem photograph.

The small head in the bottom right corner was connected to the blackened face above it with a thin red ribbon. The inspector stood in front of the board with his skeletal admin officer, pointing at things while she took notes in longhand. Insch glanced up, saw Logan and called him over, dismissing the woman with a couple of fizzy cola bottles.

'What can I do for you, sir?'

'This lot.' Insch tapped a photograph of a human head that looked like a side of barbecued pork. 'Remember we got that list of Graham Kennedy's school chums?' He stuffed a handful of the sweets into his mouth, mumbling as he chewed. 'Graham you know, but this is Ewan, Mark, Janette and Lucy.' Poking the post mortem photos one by one, leaving behind little sparkling fingerprints. 'All identified by their dental records. According to the hospital the wee girl,'" he didn't poke her picture, 'belonged to Lucy.

Gemma… poor wee sod.' Sigh. 'Anyway, we got five names from Graham's granny: one, two three, four. One missing.'

'So, who wasn't on the menu that night?'

'Karl Pearson. Twenty-four. Lives with his mum and dad in Kingswells, or he did until about three weeks ago. They got a call from him looking for some money Wednesday before last, but that was it. Haven't heard from him since.'

He pulled a holiday snap from his inside pocket showing a lumpy young man with a broken nose and a single eyebrow stretched across his face. He looked like the kind of person who would quite happily start a fight at a football match, just for the hell of it.

Logan studied the picture for a minute. 'You think he's the torch?'

Insch nodded. 'Been in trouble a couple of times for burning things that weren't his. Neighbours' sheds, an abandoned caravan, that pitch-and-putt hut down at the beach.'

That was him?'

'The very man. I've put out a lookout request, but I also have a couple of addresses.' An evil smile split the inspector's huge, bald head. 'Thought you might fancy the exercise.'

'What about your DS, you know, the bearded one?'

'What, Beattie?' DI Insch stuck his hands in his pockets, making the already groaning material bulge alarmingly.

'Bugger that. Lazy sod couldn't catch clap in a Dundee whorehouse, let alone crooks.'

'I'm supposed to be helping DI Steel, she-'

'Already OKed it with me. You're not needed till the operation tonight. Grab your coat.'

'But-'

Insch dropped his voice, laying a huge ham-like hand on Logan's shoulder. 'Thought you wanted off the Screw-Up Squad: this is your chance.' He turned and lumbered out of the room, grabbing PC Steve by the collar on his way past.

Logan hesitated, looking from the inspector to the photo gallery of death. Bloody DI Steel, trading him off to Insch without even consulting him! Muttering obscenities, Logan followed on behind.

The first address for Karl Pearson was no use, neither were numbers two, three or four. No one had seen him in ages.

Four down, two to go. Address number five was halfway up a block of flats in Seaton – down where the River Don meets the sea – one of a set of four seventeen-storey buildings with spectacular views out over the water. Lovely on a clear summer's day and bloody freezing in the dead of winter, when the wind roared in off the North Sea, fresh from the Norwegian fjords. Logan and Insch headed inside, leaving PC Steve downstairs to watch the front door.

Sixth floor, corner apartment. Insch marched straight up to Karl Pearson's alleged flat and did his policeman's knock, putting his weight behind it. Making the door boom and rattle as if God himself had come to announce judgment day.

No response.

Insch launched into his wrath-of-God routine again and a door cracked open down the hall. The occupant took one look at the huge man pounding on the corner flat's door and hurried back inside.

'Think they'll call the police?' asked Logan.

'Doubt it, but just in case…' Insch dragged out his mobile phone and called Headquarters, letting them know that the thug trying to break into the corner flat was him, so not to bother sending out a squad car. While he was doing that, Logan squatted down and peered in through the letterbox. A small hallway decorated with Aberdeen Football Club posters and pages torn from FHM magazine – half-naked women and footballers: an adolescent boy's dream – coats hanging on a set of hooks, mirror on the other side, scabby-looking golf clubs leaning in the corner, a little mudslide of junk mail on the mat. There was a door at the far end, slightly ajar, leading into what looked like a kitchen. Four more doors led off the little corridor, but only one of them was open and Logan couldn't really see into the room. He was about to give up when suddenly he got the feeling someone was staring at him … And then his eyes drifted to the hall mirror again. Someone was staring at him through the reflected lounge door, only Logan was pretty sure they couldn't actually see him. They couldn't see anything, not with their throat lying wide open like that, dark brown blood covering everything.