I said, ‘I’ve ignored eejits before. I can do it again.’ Hoped to Jaysus the squad room would be empty whenever we walked in there. Last thing I wanted to do was pick between pissing off Conway and pissing off the Murder lads.

Conway kept up the stare for another moment. Then: ‘Right,’ she said. ‘You better be good at it.’ She clicked her phone to black, slid it back into her pocket. ‘Time to talk to Selena.’

I glanced around the beds. Shoved Alison’s locker back into place, pulled Joanne’s duvet straight. ‘Where?’

‘Her room. Keep it casual, keep her relaxed. If she comes out with it . . .’

If Selena said rape, then parent or guardian, support officer, video camera, all the bells and whistles. I asked, ‘Who does the talking?’

‘I do. What’re you looking at? I can do sensitive. And you think she’ll talk to you about a rape? You stay back and try to disappear.’

Conway slammed the window shut. Before we got out of the room, the smell of body sprays and hot hair was rising around us again.

To keep the girls occupied, God help them, McKenna had started a singalong. Their voices straggled down the corridor to meet us, thin and threadbare. O Mary, we crown thee with blossoms today . . .

The common room was too hot, even with the windows open. The dinner plates were scattered around, mostly barely touched; the smell of cooled chicken pie turned me starving and queasy at the same time. The girls’ eyes were glazed and ricocheting, to each other, the windows, to Alison huddled in an armchair under a pile of hoodies.

Half of them were barely moving their lips. Queen of the angels and queen of the may . . . It took them a second to notice us. Then the voices faltered and died.

‘Selena,’ Conway said, barely a nod to McKenna. ‘Got a minute?’

Selena had been singing along, absently, gazing into nowhere. She looked at us like she was trying to work out who we were, before she got up and came.

‘Remember, Selena,’ McKenna told her, as she passed, ‘if at any point you feel in need of support, you can simply put a stop to the interview and ask to have me or another teacher present. The detectives are aware of that.’

Selena smiled at her. ‘I’m fine,’ she said, reassuring.

‘She is, of course,’ Conway said cheerfully. ‘Hang on for us in your room, yeah, Selena?’

As Selena wandered off down the corridor: ‘Julia,’ Conway said, beckoned. ‘Come here a sec.’

Julia had her back to us, hadn’t moved when we came in. In the second when she turned around, she looked wrecked: grey and tense, all the spark faded out of her. By the time she reached us she’d found a last bit of zip somewhere, gave us the smart eye again.

‘Yeah?’