‘It gets hot in here,’ she was telling him. ‘All the hard drives we keep running. Take off your jacket if you like.’

He gave a thin smile: all the time he’d been trying to read her, she’d been reading him, too. He dispensed with the jacket, draping it across his knees. When Inglis and Gilchrist exchanged a glance, he knew it was to do with his braces.

‘Other problem with our “client base”,’ she went on, ‘is that they’re getting smarter all the time. They know the hardware and software better than we do. We’re always trying to catch up. Here’s an example.’

She had nudged the mouse on her desk with her wrist. The computer screen, which had been blank, now showed a distorted image.

‘We call this a “swirl”,’ she explained. ‘Offenders send each other pictures, but only after they’ve encrypted them. Then we need to devise software to allow us to un-swirl them.’ With a click of the mouse, the photo began to resolve itself into an image of a man with his arm around an Asian boy. ‘You see?’ Inglis asked.

‘Yes,’ Fox said.

‘Plenty of other tricks, too. They’ve gotten so they can hide images behind other images. If you don’t know that’s the case, you might not bother stripping them out. We’ve seen hard drives hidden inside other hard drives…’

‘We’ve seen everything,’ Gilchrist stressed. Inglis looked across at her colleague.

‘Except we haven’t,’ she reminded him. ‘Every week there’s something new, something more revolting. All of it accessible twenty-four seven. You sit at your computer at home, surfing, maybe buying stuff or reading the gossip, and you’re about four clicks away from hell.’

‘Or heaven,’ Gilchrist interrupted, eyes fixed on his own screen. ‘It’s all a matter of taste. We’ve got stuff that would make the hairs on your scrotum stand on end.’

Fox knew that the Chop Shop considered itself a breed apart, different from the other cops at Fettes HQ: thicker-skinned, resilient, toughened by the job. A macho outfit, too. He wondered how hard Annie Inglis had worked in order to fit in.

‘You’ve got my attention,’ was all he said. Inglis was tapping at her screen with the tip of a ballpoint pen.

‘This guy here,’ she said, indicating the man with the Asian boy. ‘We know who he is. We know quite a lot about him.’

‘Is he a cop?’

She looked at Fox. ‘What makes you ask?’

‘Why else would I be here?’

She nodded slowly. ‘Well, you’re right. But our man is an Aussie, based in Melbourne.’

‘And?’

‘And, like I say, we know a lot about him.’ She opened a folder and brought out some sheets of paper. ‘He runs a website for like-minded people. There’s an entrance fee to be paid before they come aboard.’

‘They have to share,’ Gilchrist said. ‘Twenty-five pics minimum. ’

‘Pics?’

‘Of them with kids. Share and share alike…’

‘But there’s a nominal cash fee, too, paid by credit card,’ Inglis added. She handed Fox the top two sheets, a list of names and numbers. ‘Recognise anyone?’

Fox went down the list twice. There were almost a hundred names. He shook his head slowly.

‘J. Breck?’ Inglis announced. ‘The J’s for Jamie.’

‘Jamie Breck…’ The name did mean something. Then Fox got it. ‘He’s Lothian and Borders,’ he said.

‘Yes, he is,’ Inglis agreed.

‘If it’s the same Jamie Breck.’

‘Credit card comes all the way back to Edinburgh. To Jamie Breck’s bank, in fact.’

‘You’ve already checked?’ Fox handed back the list. Inglis was nodding.

‘We’ve already checked.’

‘Okay, then. So where do I come in?’

‘As of right now, his credit card’s all we’ve got. He’s not posted the photos yet – maybe he’s not going to.’

‘The site’s still active?’

‘We’re hoping they don’t catch wind of us, not until we’re good and ready.’

‘Members in over a dozen countries,’ Gilchrist broke in. ‘Teachers, youth leaders, church ministers…’

‘And none of them know you’re on to them?’

‘Us and a dozen other forces across the globe.’

‘One time,’ Inglis added, ‘the office in London arrested a ringleader and took over the running of his site. It took the users ten days to start suspecting something…’

‘By which time,’ Gilchrist interrupted again, ‘there was plenty of evidence against them.’

Fox nodded and turned his attention back to Inglis. ‘What do you want PSU to do?’

‘Normally we would let London do the work, but this one’s local, so…’ She paused, fixing her gaze on Fox. ‘We want you to paint us a picture. We want to know more about Jamie Breck.’

Fox glanced at the image on the screen. ‘And it couldn’t be a mistake?’ When he turned his attention back to Annie Inglis, she was giving a shrug.

‘Chief Inspector McEwan tells us you’ve just busted Glen Heaton. Breck works in the same station.’

‘So?’

‘So you can talk to him.’

‘About Heaton?’

‘You make it look as though it’s about Heaton. Then you tell us what you think.’

Fox shook his head. ‘I’m not a well-liked man around those parts. I doubt Breck would give me the time of day. But if he’s dirty…’

‘Yes?’

‘We can look into it.’

‘Surveillance?’

‘If necessary.’ He had her attention now, and even Gilchrist had stopped what he’d been doing. ‘We can look at what he gets up to on his computer. We can scrutinise his personal life.’ Fox paused, rubbing at his forehead. ‘The credit card’s all you’ve got?’

‘For now.’

‘What’s to stop him saying someone else must’ve used it?’

‘That’s why we need more.’ Inglis had swivelled in her chair so that her knees were a millimetre from his. She leaned forward, elbows resting on her thighs, hands clasped. ‘But he can’t suspect anything. If he does, he warns all the others. We’ll lose them.’

‘And the kids,’ Fox added quietly.

‘What?’

‘It’s all about the kids, right? Child protection?’

‘Right,’ Gilchrist said.

‘Right,’ Annie Inglis echoed.

Fox was a few steps short of the Complaints office when he stopped. He’d put his jacket back on, and was running his fingers down the lapels, just for something to do. He was thinking about DS Anthea Inglis (who preferred to be known as Annie) and her colleague Gilchrist – he didn’t even know the man’s rank or first name. Thinking, too, about the whole Chop Shop operation. PSU might be called ‘the Dark Side’, but he got the feeling Inglis and her colleague would daily peer into more darkness than he would ever know. All the same, they were a cocky bunch. At PSU, you knew everybody hated you, but CEOP was different. Fellow cops didn’t like the thought of what you’d seen, and wouldn’t talk to you for fear of what you might open their eyes and minds to. Yes, that was it: the Chop Shop was feared. Properly feared, in a way the Complaints wasn’t. Behind the locked door of 2.24 lurked a lifetime’s supply of nightmare and bogeyman.

‘Malcolm?’ The voice came from behind him. He turned to see Annie Inglis standing there, arms folded, legs slightly parted. She came towards him, her eyes fixed on his. ‘Here,’ she said, holding something out in front of her. It was her business card. ‘It’s got my mobile and my e-mail, just in case you feel the need.’

‘Thanks,’ he said, pretending to study the printed lines. ‘I was just…’

‘Just standing there?’ she guessed. ‘Thinking about everything?’

He took out his wallet, sliding one of his own cards from it. She accepted it with a little bow of the head, turned and walked back along the corridor. An elegant walk, he decided. A woman sure of her abilities, confident in her own skin, aware she was being scrutinised. Nice arse, too.

The PSU office was a lot noisier than it had been. Bob McEwan was at his desk, busy with a phone call. He saw Fox coming towards him and made eye contact, nodding to let him know it was okay. McEwan’s desk was always tidy, but Fox knew this was because everything got tipped into its half-dozen drawers on a regular basis. Tony Kaye had gone looking for paracetamol one day and had called Fox and Naysmith over to take a look.