Setting up for an insanity defence, I’d have thought, if she’d been older or savvier. If we’d been indoors, I’d’ve thought there was no setup about it, just plain insanity. But here, in the glowing spin and slipslide of her world, in the air thick with scents and stars: for a second I almost saw what she meant. Caught the edge of understanding, swung by my fingertips, before I lost hold and it soared up and away again.

Rebecca said, ‘That’s why I left him the flowers.’

‘Flowers,’ I said. Nice and neutral. Like the air hadn’t leaped into a hum around me.

‘Those.’ Her arm rose, thin as a dark brushstroke. Pointed at the hyacinths. ‘I picked some of those. Four; one for each of us. I put them on his chest. Not to say sorry, or anything; it wasn’t like that. Just to say goodbye. To say we knew he wasn’t worthless.’

Only the killer had known about those flowers. I felt, more than heard, a long sigh come out of Conway and spread across the clearing.

‘Rebecca,’ I said gently. ‘You know we have to arrest you. Right?’

Rebecca stared, huge-eyed. She said, ‘I don’t know how.’

‘That’s OK. We’ll walk you through everything. We’ll find someone to look after you till your parents can get here.’

‘I didn’t think this would happen.’

‘I know. Right now, all you need to do is come over here and we’ll go indoors.’

‘I can’t.’

Selena said, ‘Give us a minute first. Just a minute.’

I heard Conway breathe in for the No. I said, ‘We can do that. But it’ll only be a minute.’

‘Becs,’ Selena said, so softly. ‘Come here.’

Rebecca turned towards her voice, hands reaching, and her head bent back into that dark shape. Their arms folded around each other’s shoulders like wings, drawing tighter, like they were trying to meld themselves into one thing that could never be prised apart. I couldn’t tell which one of them sobbed.

Footsteps behind me, running, and this time I could turn. Holly, hair spraying out of its ponytail, leaping up the slope in great desperate bounds.

Behind her, and making himself take his time, was Mackey. He had seen her coming, gone down to the path to keep her there as long as he could. He had left me and Conway up here, to do whatever we were going to do. In the end, for his own reasons, he had decided I was worth trusting.

Holly came past Conway like she was nothing, hit the edge of the clearing, and saw the other three. She pulled up like she’d smacked into a stone wall. Said, voice cracking wild, ‘What’s happened?’

Conway kept her mouth shut. This was mine.

I said quietly, ‘Rebecca’s confessed to killing Chris Harper.’