The corner of Conway’s mouth went up. She held up her empty hands.

I said, ‘And he went down.’

‘Got him here.’ She put the edge of her hand against the back of my skull, high up and to the left of the centre line, slanting up from left to right. ‘Chris was a couple of inches shorter than you: five foot ten. The killer wouldn’t’ve had to be tall. Over five foot, under six, was all Cooper could say from the angle of the wound. Probably right-handed.’

Her feet rustling, as she moved back from me. ‘The grass,’ I said. ‘Was it like this back then?’

Right question again, good boy. ‘Nah. They let it grow afterwards – some kind of memorial thing or the place spooks the groundskeepers, I don’t know. No one sees this part, so I guess it doesn’t ruin the school’s image. Back then, though, the grass was like the rest: short. If you had soft shoes, you could sneak across it without getting heard, no problem.’

And without leaving shoeprints, or at least none that the Bureau could use. The paths were pebbled: no prints there, either.

‘Where’d you find the hoe?’

‘Back in the shed, where it belonged. We spotted it because it matched what Cooper said about the weapon. The Bureau took about five seconds to confirm it. She – he, she, whatever – she’d tried to clean off the blade, smacked it into the earth over there a couple of times’ – the ground under one of the cypresses – ‘rubbed it on the grass. Smart; smarter than wiping it down with a cloth, then you’ve got the cloth to get rid of. But there was still plenty of blood left.’

‘Any prints?’

Conway shook her head. ‘The groundskeepers’. No one else’s epithelials, either, so no touch DNA. We figured she wore gloves.’

‘“She,”’ I said.

Conway said, ‘That’s what I’ve got. A load of shes and not a lot of hes. Back last year, one theory was it was some pervert, snuck in here to crack one off watching the girls’ windows or playing with their tennis rackets or whatever; Chris came in to meet someone, caught the guy out. Doesn’t fit the evidence – what, the guy had his mickey in one hand and a hoe in the other? – but a lot of people liked it anyway. Better than thinking it was some cute little rich girl. From a beautiful school like this.’

The slant to the eye again. Testing. A cross-beam of sun lightened her eyes to amber, like a wolf’s.

I said, ‘It wasn’t an outsider. Not with that postcard. If it had been, why all the secrecy? Why wouldn’t the girl just ring you up and tell you what she knew? If she’s not making up the lot, then she knows something about someone inside the school. And she’s scared.’

Conway said, ‘And we missed her first time round.’

A grim layer stamped on her voice. Not just hard on other people, Conway.