‘There were things you suspected and things you could have asked.’ Fox gave a shrug. ‘But nothing you should be beating yourself up about – unless you know different?’ His eyes were still on the road ahead. When Clarke decided the question didn’t really need answering, he seemed content enough.

By the time they’d parked and were approaching Leith police ­station, Fraser Mackenzie was leaving, accompanied by a silver-haired lawyer who looked both distinguished and expensive. Clarke and Fox climbed to the MIT office. Trask’s door was closed, Esson back at her desk.

‘So what did he say?’ Clarke demanded.

Esson stopped typing. ‘Apparently it’s a COVID thing. Anyone on the front line – NHS, police, you name it – merits a discount as a thank-you for everything they’ve done. I did ask who else had benefited from the offer, but he couldn’t immediately think of any examples. Nor is it public knowledge.’

‘A pack of lies, in other words.’ Clarke looked towards Trask’s door. ‘How did she do?’

‘She was frosty. Both Mackenzie and his solicitor commented on it. Any idea why?’

‘The word from Gartcosh is that Mackenzie’s taken over Cafferty’s operations.’ Clarke noticed the look Fox was giving her.

‘As few people as possible,’ he said, to remind her of Dickinson’s words. All three of them turned as Tess Leighton and George Gamble walked in.

‘Not every day you visit a casino and hit the jackpot,’ Leighton said, while Gamble, breathing heavily, knocked on the door of Trask’s office. A few seconds later, Trask emerged, her eyes on Fox and Clarke.

‘Where did you two get to?’

‘Just had to pop out,’ Clarke said. ‘Sorry you ended up having to interview Fraser Mackenzie.’

‘Working the shop floor does make a change.’ Trask saw that Gamble was bursting to say something. ‘Out with it then, George.’

‘We’ve got him on film,’ Gamble obliged, having dabbed his face with a handkerchief. ‘Seemed to be spending more on drink than at the actual tables. Took some cash out of a machine – even though the casino charges for the privilege – and eventually had to be spoken to by security.’

‘Oh?’

‘He was having trouble locking his knees,’ Tess Leighton continued. ‘Staff called him a cab. There’s footage of him outside as he’s poured into it.’

‘So we’ve got a licence plate?’

‘Till’s always uses the same firm. Just need to phone them and ask who was behind the wheel that day.’

Trask nodded. ‘This gets us a bit further along, but there are gaps we still need to fill.’ She had walked to the murder wall and was studying the timeline. ‘Do we have the security footage?’

‘It’s on its way,’ Gamble assured her.