ScotiaLift occupied a featureless two-storey rectangle with a small car park in front and a gated enclosure out the back stacked with brightly coloured lifting equipment. The car park boasted a Porsche, a huge BMW four-wheel-drive thing, a soft-top Audi – none of which looked more than a couple of months old and all of which had personalized number plates – and a six-foot-tall sign with the company's logo rendered in layers of shiny plastic. Logan parked his filthy, dented CID pool car next to the Porsche, severely lowering the tone of the place, and let himself into the building's reception.

Aberdeen had a long and proud history of hiring attractive young ladies to sit behind reception desks and ScotiaLift was no exception. She smiled brightly as Logan entered. 'Can I help you?' The smile faltered as he proffered his warrant card and told her he was there to ask some questions about the disappearance of a Mr Gavin Cruickshank. She looked from the card to Logan and back again, worry making little creases at the corners of her eyes.

'I know,' he said, 'it's a dreadful photo. I need to speak to Mr Cruickshank's colleagues and anyone else who might have seen him on Wednesday.'

'But he didn't come in on Wednesday!'

Logan frowned. 'Are you sure?'

The woman nodded and tapped the reception desk with a painted fingernail. 'I would have seen him.' Logan turned and took a quick look around the reception area. It wasn't huge and the front door was directly opposite where the woman sat. She was right: if he'd come in the front she would have seen him.

There isn't a back way?'

She nodded, pointing off through an open door to the left of the desk. 'Round the side, but it opens into the yard and the gate's kept locked. Well, unless there's equipment getting moved. Everyone parks out front – I'd've seen his car.'

'In that case,' asked Logan, 'how come when Mrs Cruickshank phoned on the Wednesday afternoon she was told her husband was out with a customer?'

A slight blush. 'I don't know.'

Logan let the silence hang for a minute, hoping she'd leap in and say something more. But she didn't. Instead she took an all-consuming interest in the phones, as if willing them to ring and give her an excuse not to speak to him any more, cheeks turning redder by the minute. 'OK,' he said at last, breaking the uncomfortable silence, 'then I'll need to speak to everyone who worked with him.'

She found him an empty office on the first floor, Gavin's: an untidy room with a girlie calendar hanging on the back of the door, another one on the far wall, two computers and a huge desk that looked as if it hadn't been cleared since the last ice age. But it did have a lovely view of the car park. One by one, all of ScotiaLift's employees were called into Logan's commandeered office, from the yardsman to the managing director, sitting on the other side of the messy desk and telling Logan what a great guy Gavin Cruickshank was and how it wasn't like him to just disappear like that. None of them admitted to speaking to Gavin's wife on the phone and telling her he'd just popped out to see a client. Logan was getting ready to leave when a flashy two-seater sports car pulled up out front. He watched from his first-floor window as a tanned man in his early twenties hopped out, pointed his key fob at the car and plipped on the alarm, before swaggering towards the building and disappearing from view. Thirty seconds later the same tanned face popped around the door to Logan's office and grinned at him.

'Evenin' squire, understand you're looking for me?' Spiky blond hair, linen suit, no tie, Armani sunglasses, faint Dundee accent.

'That depends. You speak to Gavin Cruickshank's wife on Wednesday?'

'The lovely Ailsa?' The grin grew even wider as the man peeled off his jacket and hung it on a hook by the door.

'Guilty as charged. One of these days she's going to wise up and dump that tosser husband of hers.' He gave Logan a wink. 'You ever met her? Knockers like melons, sexy as hell.

Never believe she used to be the size of a house. Must go like a fucking bunny…' He sighed, happy with his fantasy.

'Wednesday afternoon: why did you tell her Gavin was out with a client?'

'Hmm? Oh, 'cos he was.'

'Funny. Everyone else says he didn't turn up for work that day.'

Pause. Fidget. And then the smile was back. 'You got me, it's a fair cop. He didn't show up Wednesday morning.'

'So why did you lie to her?'

'Well, you see, it's kinda like this: sometimes he doesn't come in till later. Sometimes he doesn't come into the office at all. Gav brings in a lot of business, so he can get away with murder round here.'

'So how did you know he was with a client? Did you speak to him?'

'Not as such, no. But he sent me a text message.'

'When was this?'

'Dunno, mid morning I think. Said he wouldn't be in till later, didn't say when.'

'So you assumed he was with a client?'

'Ah…' The smile flickered on and off as he settled into the chair behind the messy desk and switched on one of the computers. 'Not really, no. You see, Gav is what we call a "cheating bastard". Here…' He dug about in the piles of paper, coming out with a glossy photograph of a topless Gavin Cruickshank, surrounded by a gaggle of T-shirt-stretching blondes and brunettes bearing the legend Hooters. One of them was squeezing his tanned chest, her hand almost covering a black tattoo. They had Hooters emblazoned on their chests; he had Ailsa on his. 'Got that taken when we was in Houston for the last offshore technology conference.

He knobbed three of them in four days. Not that his poor bloody wife has any idea. She still thinks he's Mister Shiny.'

He shook his head. 'Unbe-fucking-lievable isn't it? I mean if you could go home and screw someone like Ailsa, why the hell would you need anyone else? But there you are: he's an arsehole.'

'So when he sent you a text saying he wouldn't be in until later, you thought 'That he was off getting his knob sucked by some lovely young thing? Yeah. Wouldn't be the first time.'

'Any idea who?'

'Well, you met Janet on reception? He's been poking her off and on for a bit. I think he's been giving one of your lot's wife a good seeing to. Detective Sergeant something or other.

And he's been seeing this pole-dancer at Secret Service, you know, the titty bar on Windmill Brae? Hayley…' An envious grin. "Cording to him she does some of the filthiest things with a carrot you ever seen! Criminal. Hey, maybe she's got a pimp or something and he's done for Gav? Or maybe they've just run off together. Silly bastard's talked about it often enough…' And the grin became a leer. 1 could console his poor, sexy, abandoned wife! Give her a shoulder to cry on and a knob to bounce on. Jesus, that would be sweet.'

Back outside in the sunshine Logan stood in the car park, looking up at the building Mr Gavin Cruickshank ran his empire of extramarital sex from. Four women – how did he have the energy? Logan had enough trouble with one.