This had been checked, the tours were informal, parties of a dozen or more at a time. There was no written record. `Could be they knew about the building work and reckoned the body would be down here for weeks.’

`Or maybe,' said Rebus, `the building work is the reason they were down here in the first place. Someone might have tipped them off. We're checking everyone.’

`Is that why we're here just now? Giving the crew a once-over?’

Rebus nodded, and Holmes nodded back. Then he had an idea. 'Maybe it was a way of sending a message.’

`That's what I've been wondering. But what kind of message; and who to?’

`You don't go for the IRA idea?’

`It's plausible and implausible at the same time,' Rebus said. `We've got nothing here to interest the paramilitaries.”

`We've got Edinburgh Castle, Holyrood Palace, the Festival…’

'He has a point.’

They turned towards the voice. Two men were standing in torchlight. Rebus recognised neither of them. As the men came forwards, Rebus studied both. The man who had spoken, the slightly younger of the two, had an English accent and the look of a London copper. It was the hands in the trouser pockets that did it. That and the air of easy superiority that went with the gesture. Plus of course he was wearing old denims and a black leather bomber-jacket. He had close cropped brown hair spiked with gel, and a heavy pockmarked face. He was probably in his late-thirties but looked like a forty-something with coronary problems. His eyes were a piercing blue. It was difficult to meet them. He didn't blink often, like he didn't want to miss any of the show.

The other man was well-built and fit, in his late-forties, with ruddy cheeks and a good head of black hair just turning silver at the edges. He looked as if he needed to shave two or even three times a day. His suit was dark blue and looked straight off the tailor's dummy. He was smiling.

'Inspector Rebus?’

'The same.’

'I'm DCI Kilpatrick.’

Rebus knew the name of course. It was interesting at last to have a face to put to it. If he remembered right, Kilpatrick was still in the SCS, the Scottish Crime Squad.

'I thought you worked out of Stuart Street, sir,' Rebus said, shaking hands.

'I moved back from Glasgow a few months ago. I don't suppose it made the front page of the Scotsman, but I'm heading the squad here now.’

Rebus nodded. The SCS took on serious crimes, where cross-force investigations were necessary. Drugs were their main concern, or had been. Rebus knew men who'd been seconded to the SCS. You stayed three or four years and came out two things: unwillingly, and tough as second-day bacon. Kilpatrick was introducing his companion, 'This is DI Abernethy from Special Branch. He's come all the way from London to see us.’

'That takes the biscuit,' said Rebus.

'My grandad was a Jock,' Abernethy answered, gripping Rebus's hand and not getting the joke. Rebus introduced Holmes and, when she returned, Siobhan Clarke. From the colouring in Clarke's cheeks, Rebus reckoned someone along the way had made a pass at her. He decided to rule out Mr Blair-Fish, which still left plenty of suspects.

'So,' said Abernethy at last, rubbing his hands, 'where's this slaughterhouse?’

'A butcher's actually,' Mr Blair-Fish explained.

'I know what I mean,' said Abernethy. Mr Blair-Fish led the way. But Kilpatrick held Rebus back.

'Look,' he whispered, 'I don't like this bastard being here any more than you do, but if we're tolerant we'll get rid of him all the quicker, agreed?’

'Yes, sir.’

Kilpatrick's was a Glaswegian accent, managing to be deeply nasal even when reduced to a whisper, and managing, too, to be full of irony and a belief that Glasgow was the centre of the universe. Usually, Glaswegians somehow added to all this a ubiquitous chip on their shoulder, but Kilpatrick didn't seem the type.

'So no more bloody cracks about biscuits.’

'Understood, sir.’

Kilpatrick waited a moment. 'It was you who noticed the paramilitary element, wasn't it?’

Rebus nodded. 'Good work.’

'Thank you, sir.’

Yes, and Glaswegians could be patronising bastards, too.

When they rejoined the group, Holmes gave Rebus a questioning look, to which Rebus replied with a shrug. At least the shrug was honest.

'So they strung him up here,' Abernethy was saying. He looked around at the setting. 'Bit melodramatic, eh? Not the IRA's style at all. Give them a lock-up or a warehouse, "something like that. But someone who likes a bit of drama set this up.’

Rebus was impressed. It was another possible reason for the choice of venue.

'Bang-bang,' Abernethy continued, 'then back upstairs to melt into the crowd, maybe take in a' late-night revue before toddling home.’

Clarke interrupted. 'You think there's some connection with the Festival?’

Abernethy studied her openly, causing Brian Holmes to straighten up. Not for the first time, Rebus wondered about Clarke and Holmes.

'Why not?’

Abernethy said. 'It's every bit as feasible as anything else I've heard.’

'But it was a six-pack.’ Rebus felt obliged to defend his corner.

'No,' Abernethy corrected, 'a seven-pack. And that's not paramilitary style at all. A waste of bullets for a start.’

He looked to Kilpatrick. 'Could be a drug thing. Gangs like a bit of melodrama, it makes them look like they're in a film. Plus they do like to send messages to each other. Loud messages.’

Kilpatrick nodded. 'We're considering it.’

'My money'd still be on terrorists,' Rebus added. 'A gun like that-‘

'Dealers use guns, too, inspector. They like guns. Big ones to make a big loud noise. I'll tell you something, I'd hate to have been down here. The report from a nine-millimetre in an enclosed space like this. It could blow out your eardrums.’

'A silencer,' Siobhan Clarke offered. It wasn't her day. Abernethy just gave her a look, so Rebus provided the explanation.

'Revolvers don't take silencers.’

Abernethy pointed to Rebus, but his eyes were on Clarke's. 'Listen to your Inspector, darling, you might learn something.’

Rebus looked around the room. There were six people there, four of whom would gladly punch another's lights out.

He didn't think Mr Blair-Fish would enter the fray.

Abernethy meantime had sunk to his knees, rubbing his fingers over the floor, over ancient dirt and husks.

'The SOCOs took off the top inch of earth,' Rebus said, but Abernethy wasn't listening. Bags and bags of the stuff had been taken to the sixth floor of Fettes HQ to be sieved and analysed and God knew what else by the forensics lab.

It occurred to Rebus that all the group could now see of Abernethy was a fat arse and brilliant white Reeboks. Abernethy turned his face towards them and smiled. Then he got up, brushing his palms together.

'Was the deceased a drug user?’

'No signs.’

'Only I was thinking, SaS, could be Smack and Speed.’

Again, Rebus was impressed, thoroughly despite himself. Dust had settled in the gel of Abernethy's hair, small enough motes of comfort.

'Could be Scott and Sheena,' offered Rebus. In other words: could be anything. Abernethy just shrugged. He'd been giving them a display, and now the show was over.

'I think I've seen enough,' he said. Kilpatrick nodded with relief. It must be hard, Rebus reflected, being a top cop in your field, a man with a rep, sent to act as tour guide for a junior officer… and a Sassenach at that.

Galling, that was the word.

Abernethy was speaking again. 'Might as well drop in on the Murder Room while I'm here.’

'Why not?’ said Rebus coldly.

'No reason I can think of,' replied Abernethy, all sweetness and bite.

'And what you've got doesn't make much sense.’