Meanwhile, Rita was halfway out of the door, already staring down at her phone.

‘It was just the smallest bit of a pencil,’ he said to Bridgette. ‘And it might take us to a killer. Don’t you find that even slightly exciting?’

‘I’ll take dried sperm any day of the week. Sorry, just the way I am.’

He knew. The whole of Elland Road knew. Her divorce last year had briefly been the most talked about in the District. It wasn’t sperm that did it, though. It was human hairs. She’d found the same hairs in her husband’s underpants on various occasions and had kept them for analysis. They were all from the same person, and it wasn’t her. Or him.

‘Tell you what, though,’ she said, stopping what she was doing, just for a second. ‘If my green paint leads to an arrest, there’s a drink in it for me.’

‘Done.’

He folded the sheet of paper and was about to leave.

‘By the way,’ she added, a half-decent smile on her face, ‘pencils are better. Than dried sperm, I mean. And Gaia Office Supplies? It’s the sales director you’ll want to talk to. I texted you her name and number. A text message? Is that OK?’

He nodded. ‘Thanks. Text, yeah, that’s good.’

‘I would’ve used WhatsApp, but, y’know.’

‘I’m on the WhatsApp! Send me a WhatsApp! I’m a fluent WhatsApper!’

Her smile broadened. ‘Joe Romano on WhatsApp? Who knew!’

By the time they were back in the operations room, Bridgette’s message had already appeared on his WhatsApp. Her tiny profile photo was an enlargement of a dust mite, the motto below her name: There’s no escape. She’d re-sent the details for Gaia Office Supplies, no additional message, no gratuitous ‘x’ or ‘lol’, or one of those grinning emojis. He replied:

Thanks for that. BTW it’s Delphic Oracles.

A moment later, another message appeared: a photo of a woman’s hand, the middle finger extended upwards. Fair.

Rita was now going through the various phone numbers on the Gaia Office Supplies website, and getting voicemail each time.