Halfway down, just visible through the swirling fog, was a WPC, lying on her back in the middle of a massive clump of nettles. Her shirt and jumper had been pulled up to her shoulders as she'd careered down the slope, exposing white skin already starting to go red with nettle stings. She was swearing a blue streak. 'Are you OK?' called Sergeant Fish-Face.

More swearing.

With a start Logan realized Jackie was standing at the lip of the slope, looking down at the thrashing figure as the woman stung herself more and more thoroughly with every flailing attempt to rise. 'WPC Buchan,' said Jackie, pointing.

'Guess she must've slipped…' She smiled.

Five minutes later they'd extricated Buchan from the nettle-infested slope. Puffing, wheezing, scratching and swearing, she clambered back up, looking daggers at WPC Watson the whole way. She was lurid-red from the under wire of her bra right down to the waistband of her trousers.

Everything in between was swollen and lumpy and itchy and stinging and she couldn't even pull down her blouse and jumper because it just made it hurt more and… and … Sergeant Fish-Face sent her home. As she limped down the trail, arms out to the sides so as not to touch the painful red rash that circled her torso, the sergeant confided in Logan that it couldn't have happened to a nicer person. Jackie just winked at him.

'You didn't have anything to do with that, did you?' he asked when they were alone again.

She grinned. 'Nobody calls my man names and gets away with it.'

Logan left them to it, smiling all the way down the hill, back to the main path. It was ten to one, according to his watch. If he and DI Steel hurried they could get back to FHQ and grab a bite to eat before Isobel launched into the post mortem at half past. He took a shortcut, labouring up the hill at the side of the track, making for the clearing and its menacing sculptures. As he crested the rise the fog took on a golden glow. A single shaft of sunlight had pierced the white gloom, spotlighting the edge of the clearing where two men in black suits were manhandling a blue plastic body bag into a brushed metal coffin, ready for its trip to the morgue. DI Steel was talking to the Procurator Fiscal, pointing at things and nodding seriously as the Fiscal replied. Logan waited on the periphery while they went over the details of the crime scene. Someone coughed beside him and Logan turned to see the new deputy PF standing in full SOC costume, her curly hair escaping from the elastic around the hood, framing her face. Her green eyes glittered above the mask. 'How's the search coming?' she asked. Logan told her, leaving out the bad language and WPC Buchan's fall. Rachael nodded as he finished, as if she'd been expecting this all along. 'I see…' A long pause to convey deep thought. 'What did you make of the handbag?'

'Why did he leave it behind you mean?' He paused, thinking about it. 'Two options: one, he's leaving us a message – something in the bag, or removed from the bag, is supposed to tell us something; option two – it was a mistake. Maybe she threw it at him and he couldn't find it again in the dark, after he'd finished with her. Or she dropped it running away…' He shrugged. 'Difficult to tell with only two bodies what is and isn't part of the pattern.'

'Only two bodies? Jesus.' Rachael looked out at the crime scene, the rotting bison, the little metal walkway, the cordons of Police tape. 'How many more of these do we need?' He was about to answer that when DI Steel beckoned him over and he had to go through the whole search update all over again: no one had found anything.

It was always a long shot,' Steel told the Fiscal, 'after all this time out in the open and the rain, but I'm not taking any chances.' She squared her shoulders and raised her pointy chin, stretching out the sagging skin beneath it.

'There's a killer out there and we're going to catch the bastard.'

Logan tried not to gag. That was the cheesiest thing he'd heard all week. But the PF seemed impressed. She too struck a determined pose, asked them to keep her posted – if there was anything she could do, etc. – and left them to it, taking her deputy with her. Rachael looking back over her shoulder, her emerald-green eyes meeting Logan's for a moment, then she was gone. He watched her disappear into the fog, before speaking. 'Laid it on a bit thick, didn't you?'

Steel shrugged and pulled an empty cigarette packet from her pocket, shaking it and peering inside as if that would somehow magically make some fags appear. 'Position we're in, we need all the friends we can get. Now the PF and Madame Frizzy-Hair go back and tell the Chief Constable we're not fucking this whole thing up. That we're doing things by the book.' She smiled and crumpled the empty pack in her hand. 'Things are starting to go our way, I can feel it in my water.'

'Of course, you realize this means Jamie McKinnon isn't a serial killer,' he said watching as the funeral directors carried the coffin out of the clearing. 'If the victim was killed three days ago that's Friday night – Jamie was banged up in Craiginches.'

Steel sighed. 'I know, but a girl can dream, can't she?'

Half past one on the dot and the morgue at Force Headquarters was getting crowded. In addition to Isobel, her assistant Brian, DI Steel and Logan, the Deputy Procurator Fiscal was here with her boss, and the corroborating pathologist – Doc Fraser, an IB photographer, the detective chief superintendent in charge of CID, the Deputy and Assistant Chief Constables. It was like a who's who of Aberdeen law enforcement, all of them worried about the possibility of another serial killer preying on the city. Knowing it would turn into a political nightmare as soon as the media found out. Even God himself had turned up; the Chief Constable being given pride of place at the head of the table. Logan wondered if he'd be saying grace before Isobel started carving.

Logan could almost smell the anticipation in the room as Isobel began her external examination of the body on the slab. According to her instructions the Identification Bureau techies, who'd picked over the body for trace evidence under her assistant's watchful eye, had positioned the victim exactly as she'd been on the forest floor: lying on her side, legs scissored out on the shiny, stainless steel surface, one arm up over her head. The thick purple line of pooled blood marked horizontal with spirit-level accuracy. They'd removed the blue plastic freezer bag from her head, exposing her battered face and bloodshot, bulging eyes. As if she was staring indignantly at the people gathered around the dissecting table.

Something about the tableau made Logan shiver. This wasn't like a normal post mortem, where the body was laid out on its back, all washed clean and clinically dead. Somehow, with the body arranged as it had been discovered, it was as if they were all voyeurs at the last, intimate moment of the victim's existence. As if this was part of the killer's performance.

The final scene for this bruised and brutalized actor.

Logan shivered again. PC Steve was right: he really was turning into a morbid bastard.

Three hours later Isobel's audience was pale, quiet and slightly shaky, standing in an otherwise empty briefing room on the second floor. A passing uniform had been dispatched to fetch coffee, not the plastic crap from the vending machine, but proper coffee reserved for high-powered meetings and special occasions. The Chief Constable reckoned they all needed it, and Logan wasn't about to disagree.

Isobel was in the corner with Doc Fraser, a modest smile on her face as he complemented her on a first-rate post mortem. Very thorough. Very revealing. Someone behind Logan muttered, 'Jesus, did she have taste peel the poor cow's face off?' Up at the front of the room, the Chief Constable finished saying something to the Procurator Fiscal and they both laughed. The new deputy fiscal managed a dutiful smile, but she was still green about the gills. When the laughter had subsided the DCC ping-ping-pinged a spoon off the side of his china cup and everyone fell silent. It was time to post mortem the post mortem. Isobel walked them through the sequence of events as she saw them, illustrating the salient points on the whiteboard with diagrams of fractured skull and ribs and limbs. Like some demonic game of Pictionary.