Excerpt from The Secret Place by Tana French, plus links to reviews, author biography & more

No point asking why anyone would want to. Teenage girls: you'll never understand.

'Yesterday evening, me and my friends were up in the art room – we're working on this project. I forgot my phone up there when we left, but I didn't notice till lights-out, so I couldn't get it then. I went up for it first thing this morning, before breakfast.'

Coming out way too pat; not a pause or a blink, not a stumble. Another girl, I'd've called bullshit. But Holly had practice, and she had her da; for all I knew, he took a statement every time she was late home.

'I had a look at the board,' Holly said. Bent to her schoolbag, flipped it open. 'Just on my way past.'

And there it was: the hand hesitating above the green folder. The extra second when she kept her face turned down to the bag, away from me, ponytail tumbling to hide her. Not ice-cream-cool and smooth right through, after all.

Then she straightened and met my eyes again, blank-faced. Her hand came up, held out the green folder. Let go as soon as I touched it, so quick I almost let it fall.

'This was on the board.'

The folder said 'Holly Mackey, 4L, Social Awareness Studies', scribbled over. Inside: clear plastic envelope. Inside that: a thumbtack, fallen down into one corner, and a piece of card.

I recognised the face faster than I'd recognised Holly's. He had spent weeks on every front page and every TV screen, on every department bulletin.

This was a different shot. Caught turning over his shoulder against a blur of spring-green leaves, mouth opening in a laugh. Good-looking. Glossy brown hair, brushed forward boyband-style to thick dark eyebrows that sloped down at the outsides, gave him a puppydog look. Clear skin, rosy cheeks; a few freckles along the cheekbones, not a lot. A jaw that would've turned out strong, if there'd been time. Wide grin that crinkled his eyes and nose. A little bit cocky, a little bit sweet. Young, everything that rises green in your mind when you hear the word young. Summer romance, baby brother's hero, cannon-fodder.

Glued below his face, across his blue T-shirt: words cut out of a book, spaced wide like a ransom note. Neat edges, snipped close.

I know who killed him

Holly watching me, silent.

From The Secret Place by Tana French. Reprinted by arrangement with Viking, a member of Penguin Group (USA) LLC, A Penguin Random House Company. Copyright © Tana French, 2014.