It was a little after three in the afternoon, and as expected they found themselves mainly talking to answerphones. They had agreed in advance on a suitably vague voicemail to leave, saying only that they needed to speak to the person in connection with a case that had a connection to St Agnes’, and left their desk numbers for them to return the call.

They did manage one success each. Porter spoke to a Jonathan Stone, who was happy enough to answer his questions, and did remember Natasha, but said they had moved in different circles. He hadn’t seen or spoken to her since they were eighteen, and had moved to Manchester after finishing university. He was no longer in touch with anyone else from school so Porter thanked him for his time and ended the call.

Styles had a little more luck. He managed to speak to a woman called Rebecca Arnold, who used to be in the school swimming team with Natasha. They hadn’t been best friends but had been close enough to invite the other to birthdays and hang out after school on occasion. She was out of town, but gave Styles her train times for coming back if someone could meet her for a chat at the station.

‘It’s not much but it’s better than nothing, I suppose,’ said Porter when Styles was finished recounting the call. ‘Coffee while we decide what’s next?’

Porter went to get the drinks while Styles called home. He was coming back through the cafeteria door, when he almost collided with two people striding down the corridor. Coffee sloshed against plastic lids. He looked up and saw Simmons and Gibson, equally as startled by his sudden appearance.

‘Shit, sorry, Evie.’ He caught himself, and hoped Gibson didn’t read anything into his use of her first name. ‘Mike.’ He nodded a greeting towards Gibson. ‘Sorry, didn’t see you there.’

‘No worries,’ said Gibson.

Porter turned to face Simmons. ‘I came to see you this morning but you were still on your way in. Have you got a few minutes now?’

‘We’re just on our way to meet Owen Carter.’ She saw his blank look and added, ‘Our man in Atlas.’

‘Ah, OK. I’ll maybe catch you later, then.’

‘I need to pay a visit before we go, so you two catch up and I’ll see you down at the car,’ said Gibson, gesturing towards the gents’ toilet.

Simmons shrugged. ‘OK, see you there.’

Gibson trotted away, leaving the two of them sharing the awkward silence. Simmons broke it first.

‘We don’t have to do the Locke catch-up now if you’re busy,’ she said, pointing at the two cups he held.

‘These? No, no, these are just for me and Styles. I’ve got a few minutes now if you do? Here, have mine,’ he said, offering her one of the cups. ‘I can pop down and get another one later.’