That cringe again, hunching down into her shoulders. Something was scaring her worse than us and Chris combined. Joanne; had to be. Joanne had wanted Chris.

Conway tapped the book. ‘When was the last time any of yous snuck out?’

‘Gemma was out like a week before what happened to Chris. I mean, how creepy is that? We were all, “OhmyGod, if there was like a serial killer stalking the school, he could totally have got her instead!”’

‘You never went out after that? Any of yous? Ah-ah’ – finger lifting again – ‘think about it before you go lying to us.’

Orla was shaking her head so hard her hair whipped her in the face. ‘No. I swear. None of us. After Chris, we weren’t exactly about to go wandering around out there. Joanne actually told me to go get that key and bin it or something, and I tried, but I was just taking the books out and oh! my God! one of the prefects came barging in? And she was all, “What are you doing in here?” ’cause it was after lights-out ’cause I couldn’t exactly do it while everyone was in the common room? I almost had a heart attack. So after that, no way was I trying again.’

Conway lifted an eyebrow. ‘Joanne was OK with that?’

‘Oh my God, she would’ve been so furious! I told her . . .’ Snorty giggle from Orla, hand going over her mouth. ‘I told her I’d done it. I mean, it’s not like anyone could tell it was ours anyway, or even what it was . . .’ Something dawned on her. ‘How’d you guys know?’

‘DNA,’ Conway said. ‘Go back to the common room.’

‘Selena and Chris,’ Conway said, watching down the corridor as the common-room door shut behind Orla. ‘Not bullshit after all.’

She didn’t sound happy about it. I knew why. Conway figured she should have got to this a year ago.

I said, ‘Unless Orla’s lying. Or Gemma lied to her.’

‘Yeah. I don’t think so, but.’ Neither did I. ‘Let’s see what Selena has to say.’

We’d get nothing out of Selena. I could feel it, in with that feeling that she was at the heart of the mystery: she was wrapped so deep in layers of it, we would never get through them to her. ‘Not Selena,’ I said. ‘Julia.’

Conway started to give me the glare. Changed her mind – I’d been right about Orla – nodded instead. ‘OK. Julia.’

Orla was at the centre of the common-room gabble, flopped on a sofa with one hand on her chest like she had the vapours, eating up the attention. Joanne looked ready to kill: Orla had come clean about not binning the key. Holly’s lot hadn’t moved, but their eyes were on Orla.