Ajay saw an old gent in a cardigan, cord trousers and a shirt and tie wander aimlessly around the office, and poked his head out of the meeting room. ‘Excuse me, can I help you?’

‘I think someone’s expecting me. I’m Anthony Eden.’ The old man peered over the top of his half-moon glasses. ‘I’m the Digital Forensic Investigator.’

‘Of course you are,’ said Craig with a frown.

After introducing himself to everyone, careful to repeat his name every single time – Anthony Eden, Digital Forensic Investigator, Anthony Eden, Digital Forensic Investigator – he placed a battered leather satchel on the table and took out a packet of Percy Pigs, a folded copy of the Telegraph, the crossword completed in small, precise handwriting, and an angling magazine. Finally, after all that, came a slim silver laptop.

Lifting the visitor pass that dangled on the end of his lanyard away from the keyboard, Anthony floated a crooked finger across the trackpad to reveal a screen full of incomprehensible data.

Sasha glanced at her watch and asked cheerily, ‘What have you got for us, Tony?’

He stood to inform her gravely, ‘It’s Anthony.’

‘Sorry,’ said Sasha. ‘Quite right. Anthony.’

Lolly covered her mouth with a hand: you got busted.

‘Now then.’ Anthony took a moment to frown at Sasha’s bare feet. ‘I’m afraid I can’t tell you who sent the photos to the young lady if that’s what you were hoping. But the good news is that the images were taken on a digital camera that contains Exif metadata.’ Ajay nodded, already way ahead of them. ‘That stands for exchangeable image file format.’

‘And what does that mean?’ asked Craig.

‘Exif data contains information about the photo itself,’ said Ajay. ‘Format, date and time, camera settings, any copyright information. And geotagging.’

Lolly’s eyes lit up. ‘GPS coordinates of where the photo was taken.’

Anthony held the packet of Percy Pigs towards her. ‘You’ve just earned a prize, young lady.’

She put her hand in the bag and popped the sweet into her mouth. Anthony turned the laptop towards Ajay, who scribbled down the coordinates on a notepad and rushed out of the room, headed towards his desk.

‘Whoever took these photos probably didn’t even know that data was being captured. It’s so difficult not to leave a trace on the world these days.’

‘To be honest, you’re not what we were expecting,’ Sasha told him.

‘Oh, you thought I’d be some young long-haired fellow in a Metallica T-shirt, I get that all the time.’ He glanced at her white hair. ‘But they haven’t got rid of all us old folk yet.’

‘Quite.’ Sasha smiled tersely, not altogether sure whether the suggestion was that she was also over the hill.