‘I’m ready,’ he told Ollie.

The initial picture on the screen was Jackson’s passport photograph from the last time. McNab thought again that the face looked like a Ukrainian terrorist or a Mafia hitman.

However, the full face wasn’t what Ollie was interested in. He’d wanted images of the man’s stance, the shape of the shoulders, the way he held his head. Trawling social media and God knows where else, he’d found a selection of such images, and now McNab was watching them spool across the screen.

The software running alongside was doing its job, checking each image by comparing it to the physical attributes of the man in the CCTV images. However, the software, no matter how powerful, wasn’t as good as Ollie, and he was just using it to prove to McNab that he was right.

Eventually the program made its decision.

The man in the various images was the missing husband of Eleanor Jackson, who was supposedly somewhere in a truck in Europe. But he wasn’t, because he’d been caught on CCTV in Stirling, within touching distance of Karen Marshall.

‘I’m checking European police records, in case he comes up in any of them,’ Ollie said. ‘So far he’s clean.’

‘Or he’s not been caught yet,’ McNab added.

‘So what now?’ Ollie said.

‘It’s time Mrs Jackson and I had another chat.’ McNab helped himself to a ring doughnut from the box he’d brought for Ollie. ‘How are things with Maria?’

‘She’s putting me on a diet,’ Ollie said.

‘No more doughnuts?’

‘She says you’re to bring me fruit instead,’ Ollie said in a crestfallen manner.

‘Irn-Bru still all right?’

‘Apparently the new one has less sugar, so she’s okayed that, in moderation.’

McNab patted Ollie on the shoulder. ‘She sounds like a keeper. I’d do what she says. You’ll live longer.’ McNab popped the last bit of doughnut in his own mouth.

There was nothing like a sugar rush at times like this.

McNab stopped by the coffee machine to add caffeine to the mix, then went to find his partner. He recalled last night’s meeting with the soon-to-be Mrs Clark, or Mrs – what was the lovely Paula’s surname? Maybe they didn’t do the Mrs thing anyway and just stayed with their own names.

He had discovered since the news of their engagement had been broken to him that he was becoming more observant of his colleagues, not wishing to be caught out again. Criminals he could read like a book. Ordinary law-abiding citizens and their sexuality obviously not so well.

He knew he was avoiding thinking about Ellie and her determined but also questioning suggestion she’d made last night. Shock had been his first and main reaction. So much so that he hadn’t slept much afterwards, his brain having decided to replay their conversation like a broken record all night long.

McNab forced himself to focus instead on Ollie’s news, and to wonder if he should visit Mrs Jackson alone or take his engaged partner along. Even as he considered this, McNab realized the likelihood was that DS Clark would be the one to decide.