I didn't get the impression that the "youths"-I hate that word-had been serious suspects. They weren't exactly hardened criminals (the local uniforms cautioned them for public intoxication on a semiregular basis, and Shane Waters had been given six months' probation for shoplifting when he was fourteen, but that was it), and why would they want to make a couple of twelve-year-olds disappear? They had simply been there, and vaguely unsavory, so Kiernan and McCabe had checked them out.

The bikers, we had called them, although I'm unsure whether any of them actually had motorbikes; probably they just dressed as though they did. Black leather jackets, unzipped at the wrists and trimmed with metal studs; stubble and long hair, and one of them had the inevitable mullet. High Doc boots. T-shirts with logos on the fronts: METALLICA, ANTHRAX. I thought those were their names, till Peter told me they were bands.

I had no idea which one had become Jonathan Devlin; I couldn't connect the sad-eyed man with the little paunch and the desk slump to any of the lean, sun-blurred, looming teenagers in my memory. I had forgotten all about them. I don't think the bikers had entered my mind once in twenty years, and I intensely disliked the thought that they had been there all along in spite of this, just waiting for their cue to pop up neatly as jacks-in-the-box, bobbing and grinning, and make me jump.

One of them wore shades all year round, even in the rain. Sometimes he offered us Juicy Fruit gum, which we took, at arm's length, even though we knew they had stolen it from Lowry's shop. "Don't go near them," my mother said, "don't answer if they talk to you," and wouldn't tell me why. Peter asked Metallica if we could have a drag of his cigarette, and he showed us how to hold it and laughed when we coughed. We stood in the sun, just out of reach, stretching to see the insides of their magazines; Jamie said one of them had a girl all nude. Metallica and Shades flicked plastic lighters, had competitions to see who could hold his finger over the flame longest. When they left, in the evening, we went over and smelled the squashed cans left behind in the dusty grass: sour, stale, grown-up.

I woke up because someone was screaming below my window. I sat up hard, my heart banging against my ribs. I had been dreaming, something tangled and feverish where Cassie and I were in a crowded bar and a guy in a tweed cap was yelling at her, and for a moment I thought it was her voice I had heard. I was disoriented, it was dark, heavy late-night silence; and someone, a girl or a child, was screaming again and again outside.

I went to the window and cautiously hooked the curtain open an inch. The complex where I live is made up of four identical apartment buildings around a little square of grass with a couple of iron benches, the kind of thing estate agents call a "communal recreation area," although nobody ever uses it (the couple in the ground-floor flat had lazy evening cocktails al fresco a couple of times, but people complained about the noise, and the management company put up a narky sign in the foyer). The white security lights gave the garden an eerie nightscope glow. It was empty; the slants of shadow in the corners were too low to hide anyone. The scream came again, high and chilling and very close, and an atavistic prickle went up my spine.

I waited, shivering a little in the cold air striking off the glass. After a few minutes something moved in the shadows, blacker against the black, then detached itself and stepped out onto the grass: it was a big dog-fox, alert and scrawny in his sparse summer coat. He raised his head and screamed again, and for a moment I imagined I caught his wild, alien scent. Then he trotted across the grass and disappeared through the front gate, pouring between the bars as sinuously as a cat. I heard his shrieks moving away into the darkness.

I was dazed and half asleep and keyed up with leftover adrenaline, and my mouth tasted foul; I needed something cold and sweet. I went out to the kitchen to look for juice. Heather, like me, sometimes has trouble sleeping, and I found myself almost hoping she would be awake and still wanting to complain about whatever it was, but there was no light under her door. I poured myself a glass of her orange juice and stood in front of the open fridge for a long time, holding the glass to my temple and swaying slightly in the flickering white light.

In the morning it was pouring rain. I texted Cassie to say I'd pick her up-the Golf Cart tends to go catatonic in wet weather. When I beeped my horn outside her flat, she ran down wearing a Paddington Bear duffle coat and carrying a thermos of coffee.

"Thank God it didn't do this yesterday," she said. "Bye-bye evidence."

"Look at this," I said, giving her the Jonathan Devlin stuff.

She sat cross-legged in the passenger seat and read, occasionally passing me the thermos. "Do you remember these guys?" she said, when she'd finished.

"Vaguely. Not well, but it was a small neighborhood and they were hard to miss. They were the nearest thing we had to juvenile delinquents."

"Did they strike you as dangerous?"

I thought about this for a while, as we crawled down Northumberland Road. "Depends what you mean," I said. "We were wary of them, but I think that was mainly because of their image, not because they ever did anything to us. I remember them being fairly tolerant of us, actually. I can't see them having made Peter and Jamie disappear."

"Who were the girls? Were they interviewed?"

"What girls?"

Cassie flicked back to Mrs. Fitzgerald's statement. "She said 'courting.' I'd say it's a safe bet that involved girls."

She was right, of course. I wasn't too clear on the exact definition of "courting," but I was pretty sure it would have excited a fair amount of comment if Jonathan Devlin and his mates had been doing it with each other. "They're not in the file," I said.

"What about you, do you remember them?"

We were still on Northumberland Road. The rain was sheeting down the windows so heavily it looked like we were underwater. Dublin was built for pedestrians and carriages, not for cars; it's full of tiny winding medieval streets, rush hour lasts from seven in the morning till eight at night, and at the first hint of bad weather the whole city goes into prompt, thorough gridlock. I wished we had left a note for Sam.

"I think so," I said eventually. It was nearer to a sensation than to a memory: powdery lemon bonbons, dimples, flowery perfume. Metallica and Sandra, sitting in a tree… "One of them might have been called Sandra." Something inside me flinched at the name-acrid taste like fear or shame at the back of my tongue-but I couldn't find why.

Sandra: round-faced and buxom, giggles and pencil skirts that rode up when she perched on the wall. She seemed very grown up and sophisticated to us; she must have been all of seventeen or eighteen. She gave us sweets out of a paper bag. Sometimes there was another girl there, tall, with big teeth and lots of earrings-Claire, maybe? Ciara? Sandra showed Jamie how to put on mascara, in a little heart-shaped mirror. Afterwards Jamie kept blinking, as though her eyes felt strange, heavy. "You look pretty," Peter said. Later Jamie decided she hated it. She washed it off in the river, scrubbing away the panda rings with the hem of her T-shirt.

"Green light," Cassie said quietly. I inched forward another few feet.

We stopped at a newsagent's and Cassie ran in and got the papers, so we could see what we were dealing with. Katy Devlin was front-page news in every one of them, and they all seemed to be focusing on the motorway link-KNOCKNAREE PROTEST LEADER'S DAUGHTER MURDERED, that kind of thing. The large tabloid reporter (whose story was headlined DIG BIGWIG'S DAUGHTER SLAUGHTER, a hyphen away from libel) had thrown in a few coy references to Druidic ceremonies but stayed clear of full-scale Satanism hysteria; she was obviously waiting to see which way the wind blew. I hoped O'Kelly would do his stuff well. Nobody, thank Christ, had mentioned Peter and Jamie, but I knew it was only a matter of time.