‘Stab wounds to the thighs, more shallow cuts to the chest, several slashes across either cheek,’ Cal informed them. ‘Looks to me like they were torturing him when they received a surprise interruption. Callahan and Fleeting were both shot in the back to bring them down, then took two each in the back of the head to finish them off. Professional. Execution-style. The guest of honour took a double tap to the head also, so it wasn’t a rescue mission. We found his wallet in the pocket of a jacket dumped over in the corner by the back door. According to the driving licence, his name was Thomas Miller. That ring any bells?’

Catherine looked at the blackened and ruined face, exit wounds having blown his features apart. His own mother wouldn’t recognise him, God help her.

‘Tommy Miller,’ she said. ‘Quintessential Glasgow fly-man. All things to all men.’ She turned to Laura. ‘One might even say an adept at playing both ends against the middle.’

‘You reckon this was Bob Cairns’ source?’

‘Frankie and Gary here appear to have believed so. I think this may answer the question of whose heroin we confiscated yesterday. Bad day all round for this pair. Lose three million quid’s worth of drugs in the morning, then get shot dead and set fire to later on.’

‘Aye. That would fuck me off,’ Laura said, mimicking Callahan’s intense sincerity. ‘It would fuck me right off.’

She looked down with contempt at what was left of Gary Fleeting. Sure didn’t look so pleased with himself now. There would be no more ‘wee durties’ happy to ‘take it all ways’ from him.

‘Who would have done this?’ she asked. ‘The wholesaler, maybe? Could be the drugs got lifted before payment was made and they weren’t prepared to just write it off against tax.’

‘Can’t see it. It’s too soon, and too extreme. The amount of heroin Frankie Callahan was moving each year, it would be bad business sense to react like this. They’d want to work something out, a compensation payment or some other make-good. When your handover strategy involves leaving the merchandise unattended, you’d have to think there would be some kind of agreement in place to cover this sort of scenario.’

‘This happened with no questions being asked. Both of them shot in the back before they could even speak, then Tommy here taken out because he was a witness. Whoever did this just wanted them dead. That suggests a simpler motive.’

That was when Laura noted the significance of the supply firm’s delivery fleet, pointing out two of them parked on the depot’s forecourt.

They were both dark blue Transit vans.