PC Rennie looked affronted again, but wisely kept his mouth shut.

The inspector buttoned his coat back up. 'Right, Logan, you're with me.' And with that they were gone.

WPC Watson watched the door close behind them with a scowl on her face.

The Bastard Simon Rennie sidled up beside her. 'Gee, Jackie,' he said in a whiny American accent. 'You're so big and special. Will you protect me if the nasty man comes back?' He even fluttered his eyelashes.

'You can be such a dick at times.' She stormed off to the kitchen to make a cup of tea.

PC Rennie, grinned to himself in the hallway then flounced after her, calling, 'Don't leave me! Don't leave me!' Out in the patrol car Logan cranked up the heaters and waited for the windscreen to turn transparent again. 'You sure about this?' he asked the inspector, who had discovered an open packet of winegums in his overcoat and was busily picking off the little bits of fluff and pocket-grit.

'Hmmm?' Insch stuffed a red one in his mouth and offered the packet to Logan. The next one down was dark green and devoid of fuzz.

'I mean,' said Logan, plucking the sweet from the roll and popping it in his mouth. 'What if he comes back?'

Insch shrugged. 'They don't call her "Ball Breaker" for nothing. I put loads of uniforms out here and they're going to scare him away. This has to be low key. I'm going to put a couple of unmarked cars down the road. If he comes back: they'll see him. But my guess is he's going to one of his little council hideyholes. And even if he is stupid enough to go home, I doubt he'll give Watson any trouble. Strichen's not got form for violence, not real violence.'

'He decked Sandy the Snake!'

Insch nodded and smiled happily. 'Yeah, at least he did some good in his life. Anyway, you and I have plenty of other things to worry about. To the Bat Cave!' He pointed a fat hand in the direction of Force Headquarters.

Logan pulled the patrol car out into the blizzard, leaving 25 Howesbank Avenue, and WPC Watson, behind.

36

Every patrol car in the city was out looking for Martin Strichen, all of them armed with the details of his scabby Ford Fiesta. Forensics had found blood on the secateurs, wedged into the hinge; it was the same type as David Reid's. If Strichen was out there they were damned well going to find him.

Four and three-quarter hours, and counting.

Back at Force Headquarters, DI Insch and DS McRae were wasting time. The big boys from Edinburgh had arrived. Two detective sergeants, both dressed in smart dark blue suits, with toning shirts and ties, one detective inspector with a face like the underside of an ashtray, and a clinical psychologist who insisted that everyone call him 'Doctor' Bushel.

The DI had run two serial killer cases, both times getting his man. The first after six strangled students had been found on Carlton Hill, overlooking the east end of Princes Street. The second after a prolonged siege in the old town. No survivors. Three members of the public and one police officer had lost their lives that time. It was not, Logan thought, a great track record.

The new inspector listened with cold hard eyes as Insch took the visiting muscle through the case to date. The DI asked some pretty searching questions along the way. He wasn't an idiot: that was clear enough. And he was impressed that Insch and Logan had managed to identify their killer after only two bodies.

Dr Bushel was so smug it was unbearable. Martin Strichen fitted the profile he'd provided perfectly – the one which said their child killer would have 'mental health problems'. He didn't seem to grasp the fact that it had been bugger all use in identifying Strichen.

'And that's where we are now,' said Insch when he'd finished, making a 'ta-da!' gesture, indicating the contents of the incident room.

The DI nodded. 'Sounds like you don't need any help from us,' he said, the words coming out low and gravely, just laced with a hint of Southern Fife. 'You know your man, you've got the search teams out. All you've got to do now is wait. He'll turn up sooner or later.'

Sooner or later wasn't good enough for Insch. Sooner or later would mean Jamie McCreath had joined the ranks of the dead.

The doctor got to his hind legs and peered at the crime scene photographs, pinned to the wall, making cryptic 'Hmmm…' and 'I see…' noises.

'Doctor?' said the DI. 'You got any idea where he's going to turn up?'

The psychologist turned, the light flashing artfully off his round glasses. He flashed a smile to go along with it. 'Your man isn't going to rush this thing,' he said. 'He wants to take his time. After all, this is something that he's been planning for a long time.'

Logan shared an oh-my-God look with Insch. 'Er…' he said, treading carefully. 'Do you not think this is more of a knee-jerk reaction?'

Dr Bushel looked at Logan as if he was an errant child, but one he was willing to indulge. 'Explain?'

'He was abused by Gerald Cleaver when he was eleven. Cleaver was found not guilty on Saturday. On Sunday we found the Lumley child before Strichen could get back and mutilate him. Today there are adverts all over the telly: Cleaver's sold his story to the papers. Strichen can't cope with it all. It's sent him over the edge.'

The doctor smiled indulgently. 'An interesting theory,' he said. 'The layperson often confuses the signs. You see, there are patterns here that only a trained eye can discern. Strichen is a highly organized offender. He takes great care to make sure his victims' remains are not discovered. He has a highly ritualized fantasy world and those rituals mean he has to abide by his own internal set of rules. If he doesn't do that then he has become nothing more than a monster preying on small children. You see, he's ashamed of what he does-' Dr Bushel pointed at a post mortem photograph of David Reid's groin. 'Pretending the child isn't male, by removing the genitalia. Telling himself his crime is less heinous, because it's not little boys he's violating.' He took off his glasses and polished them on the end of his tie. 'No, Martin Strichen must be able to justify his actions, if only to himself. He has his rituals. He will want to take his time.'

Logan didn't say another word until Insch had shown the visitors the canteen and they were alone, back in the incident room again. 'What a sack of shite!'

Insch nodded and rummaged through his pockets for the umpteenth time that afternoon. 'Aye. But that wee sack of shite has helped catch four repeat offenders, three of them murderers. He's got all the people skills of diphtheria, but he's experienced.'

Logan sighed. 'So what do we do now?'

Insch gave up on the sweetie hunt, sticking his large hands desolately into the trouser pockets of his suit. 'Now,' he said. 'Now we sit back and hope we get lucky.' In summer the rear windows would look out across rolling tufts of scrub grass, gilded with golden sun, the view stretching out to the horizon. Bucksburn's grey sprawl would be hidden by the steep hill down from the quarries. On a good day, when the paper mills weren't belching out cumulus clouds of strange-smelling steam, the hillsides, farmland and woods on the other side of the River Don would shine like emeralds. A bucolic haven, insulated from the droning traffic on the dual carriageway below.

But none of it was visible now. The snowstorm had turned into a blizzard and, standing at the master bedroom window, WPC Jackie Watson couldn't make out much beyond the back garden's fence. Sighing, she turned her back on the grey, howling afternoon and stomped back downstairs.

Martin Strichen's mum was hunched in an overstuffed armchair gaily upholstered in roses and poppies. She had a fag dangling from the corner of her mouth, and a graveyard of them sitting in the ashtray beside her. The telly was on: a soap opera. Watson hated soap operas. But the Bastard Simon Rennie loved them. He sat on the floral couch and stared at the screen, slurping away at cup after cup of tea.