‘I wish you’d asked me that three days ago,’ the officer says. ‘Our super-recogniser results have been incredible, on a par with DNA and fingerprints.’

‘So what’s happened?’ Silas asks.

He expects the detective to say that his unit’s been closed down, run out of town by some new facial-recognition software contract, but the answer stuns him.

‘Our main recogniser, an extraordinary bloke, has just gone AWOL, dropped off the grid completely.’

‘Civilian?’ Silas asks, reaching for a pen and paper.

‘Community support officer. Been with us for years, always been a good spotter.’

‘Family?’

‘They’re distraught. Wife says it’s totally out of character. He’s a man of routine. We’re all worried sick.’

Silas stands up, walks over to the window and looks out onto the deserted car park. Not many people in tonight. They’re all off on holiday, enjoying the summer, as he should be.

‘Has he been involved in any serious-crime cases recently?’ he asks.

‘Nothing major. Indecent exposure, a few assaults, shoplifting. Why?’

Silas thinks back to Kate’s track record. Should he have limited her work to identifying petty criminals? There was a lot of pressure at the time to focus on modern-slavery and organised-crime gangs. ‘It’s just that we’ve had an issue with one of our old super recognisers,’ he says.

‘What sort of issue?’

It’s well known amongst regional police forces that Swindon’s super-recogniser unit was unceremoniously wound up. Just like the Met’s unit was closed, even though the force still uses super recognisers. But no one knows about Kate and the attempts on her life.

‘Our best recogniser, a civilian, was injured in a car accident,’ Silas says. ‘The unit was shut down shortly afterwards, as you know. It now seems that it might not have been an accident. She might have been deliberately targeted – by one of the gangs she helped to convict.’

‘Is that recent?’ the officer asks, surprised.

‘We’ve only found out today. Nothing confirmed, but it looks that way. Did your PCSO do much publicity? Media interviews?’

‘We’ve kept him out of the limelight – our secret weapon.’

Silas wishes he’d done the same with Kate, not exposed her to so much media attention. It was a way of taunting his boss as much as anything. Petty.

‘We’ll double-check the list of recent convictions,’ the detective says. ‘Ones that he can claim responsibility for. I can’t see anyone taking it out on him though.’

That’s what Silas thought about Kate. And look what happened to her. ‘Let me know if he turns up,’ he says. ‘How good is he?’

‘How good? He’s a freak. More than a hundred IDs in the past year. Don’t know about you, but I’ve been twenty years in the force and can count the number of people I’ve identified on one hand.’