Damien took a can of 7-Up, but he refused the pizza; he wasn't hungry, he said. "Sure?" Cassie asked, trying to catch strings of cheese with her finger. "God, when I was a student I'd never have turned down free pizza."

"You never turn down food, period," I told her. "You're a human Hoover." Cassie, unable to answer through a huge mouthful, nodded cheerfully and gave us the thumbs-up. "Go on, Damien, have some. You should keep your strength up; we're going to be here for a while."

His eyes widened. I waved a slice at him, but he shook his head, so I shrugged and kept it for myself. "OK," I said, "let's talk about Mark Hanly. What's he like?"

Damien blinked. "Mark? Um, he's OK. He's strict, I guess, but he sort of has to be. We don't have a lot of time."

"Ever seen him get violent? Lose his temper?" I wiggled a hand at Cassie; she threw me a paper napkin.

"Yeah-no…I mean, yeah, he gets mad sometimes, if someone's messing, but I never saw him hit anyone, or anything like that."

"Do you think he would, if he was angry enough?" I wiped my hands and thumbed through my notebook, trying not to get grease on the pages. "You're such a slob," Cassie told me; I gave her the finger. Damien glanced between us, flustered and off balance.

"What?" he asked at last, uncertainly.

"Do you think Mark could get violent if he was provoked?"

"I guess maybe. I don't know."

"What about you? Ever hit anyone?"

"What…no!"

"We should've got garlic bread," Cassie said.

"I'm not sharing an interview room with two people and garlic. What do you think it would take to make you hit someone, Damien?"

His mouth opened.

"You don't seem like the violent type to me, but everyone's got a breaking point. Would you hit someone if he insulted your mother, for example?"

"I-"

"Or for money? Or in self-defense? What would it take?"

"I don't…" Damien blinked fast. "I don't know. I mean, I've never-but I guess everyone's, like you said, everyone's got a breaking point, I don't know…"

I nodded and made a careful note of this. "Would you rather a different kind?" Cassie asked, inspecting the pizza. "I think ham-and-pineapple rules, personally, but they have some macho pepperoni-and-sausage thing next door."

"What? Um-no, thanks. Who's…?" We waited, chewing. "Who's next door? Am I, like, allowed to ask?"

"Sure," I said. "That's Mark. We sent Sean and Dr. Hunt home, awhile back, but we haven't been able to let Mark go yet."

We watched Damien turn a shade paler as he processed this information and its implications. "Why not?" he asked faintly.

"Can't go into that," Cassie said, reaching for more pizza. "Sorry." Damien's eyes ricocheted, disoriented, from her hand to her face to mine.

"What I can tell you," I said, pointing at him with a crust, "is that we're taking this case very, very seriously. I've seen a lot of bad stuff in my career, Damien, but this… There's no crime in the world worse than murdering a child. Her whole life's gone, the entire community's terrified, her friends will never get over it, her family's devastated-"

"Emotional wrecks," Cassie said indistinctly, through a mouthful. Damien swallowed, looked down at his 7-Up as if he had forgotten it and started fumbling with the tab.

"Whoever did this…" I shook my head. "I don't know how he can live with himself."

"Tomato check," Cassie told me, dabbing a finger at the corner of her mouth. "Can't take you anywhere."

We finished off most of the pizza. I didn't want it-even the smell, greasy and pervasive, was too much for me-but the whole thing was getting Damien more and more flustered. He accepted a slice, in the end, and sat wretchedly picking off the pineapple and nibbling on it, his head whipping from Cassie to me and back as if he were trying to follow a tennis match from too close by. I spared a thought for Sam: Mark was unlikely to be sent into a tailspin by pepperoni and extra cheese.

My mobile vibrated in my pocket. I checked the screen: Sophie. I took it out into the corridor; Cassie, behind me, said, "Detective Ryan leaving the interview room."

"Hi, Sophie," I said.

"Hey. Here's the update: no signs that either lock was forced or picked. And the trowel's your rape weapon, all right. It looks like it's been washed, but we've got traces of blood in the cracks on the handle. We've also got a fair amount of blood on one of those tarps. We're still checking gloves and plastic bags-we'll still be checking gloves and plastic bags when we're eighty. We found a torch under the tarps, too. There are prints all over it, but they're all small and the torch has Hello Kitty on it, so I'm betting it's your victim's and so are the prints. How're you guys doing?"

"Still working on Hanly and Donnelly. Callaghan and Hunt are out."

"Now you tell me? For Christ's sake, Rob. Thanks a bunch. We've gone over Hunt's fucking car. Nothing-well, obviously. No blood in Hanly's car, either. About a million hairs and fibers and blah blah blah; if he had her in there, he wasn't worried enough to clean up after himself, so we might get a match. Matter of fact, I doubt he's ever cleaned that thing. If he ever runs out of archaeological sites, he can start work under his front seat."

I slammed the door behind me, told the camera, "Detective Ryan entering the interview room," and started clearing away the pizza things. "That was the Technical Bureau," I said to Cassie. "They've confirmed our evidence is exactly what we thought it was. Damien, are you finished with that?" I threw the pineappleless slice of pizza back into the box before he could answer.

"That's what we like to hear," Cassie said, grabbing a napkin and giving the table a quick wipe. "Damien, do you need anything before we get to work?"

Damien stared, trying to catch up; shook his head.

"Great," I said, shoving the pizza box into a corner and pulling up a chair. "Then let's start by updating you on some of what we've found out today. Why do you think we brought the four of you in here?"

"About that girl," he said, faintly. "Katy Devlin."

"Well, yeah, sure. But why do you think we only wanted the four of you? Why not the rest of the team?"

"You said…" Damien motioned to Cassie with the 7-Up can; he was clutching it in both hands, as if afraid I might take that away, too. "You asked about the keys. Who had keys to the sheds."

"Bingo," Cassie said, nodding approvingly. "Well spotted."

"Did you, um…?" He swallowed. "Did you, like, find something in one of the sheds?"

"Exactly," I said. "Actually, we found something in two of the sheds, but close enough. We can't go into details, obviously, but here's the gist of it: we've got evidence that Katy was killed in the finds shed on the Monday night and stashed in the tools shed through the Tuesday. There was no forced entry. What do you think that means?"

"I dunno," Damien said, at last.

"It means we're looking for someone who had the key. That's Mark, Dr. Hunt or you. And Hunt's got an alibi."

Damien actually half-raised his hand, as if he were in school. "Um, me, too. I mean, an alibi."

He looked at us hopefully, but we were both shaking our heads. "Sorry," Cassie said. "Your mother was asleep during the time we're looking at; she can't vouch for you. And anyway, mothers…" She shrugged, smiling. "I mean, I'm sure your mammy's honest and everything, but as a rule, they'll say whatever it takes to keep their kids out of trouble. God love them for it, but it means we can't really take their word on something this important."