"What's the highlighter?" I asked.

"I cross-referenced against the known associates, tried to split up the calls by family member. Looks like Katy's the one used the phone most: all those numbers in yellow are her mates." I flipped pages. The yellow highlighter took up at least half of each one. "The blue is Margaret's sisters-one in Kilkenny, Vera across the estate. The green's Jonathan's sister in Athlone, the nursing home where their mammy's living, and committee members of Move the Motorway. The purple's Rosalind's friend Karen Daly, the one she stayed with when she ran away. The calls between them start to dry up after that. I'd say Karen wasn't too pleased about being put in the middle of family hassle, except that she kept ringing Rosalind for a few weeks after; Rosalind just wasn't ringing her back."

"Maybe she wasn't allowed to," I said. It might have been just the start Sam had given me, but my heart was still going too fast and there was a sharp, animal taste of danger in my mouth.

Sam nodded. "The parents might've seen Karen as a bad influence. Anyway, that's all the calls accounted for, except a bunch from a phone company trying to get them to switch provider-and these three." He spread out the pages of incoming calls: three stripes of pink highlighter. "The dates, times and lengths match what Devlin gave us. They're all from pay phones."

"Dammit," Cassie said.

"Where?" I asked.

"City center. The first one's on the quays, down near the Financial Services Centre; second one's on O'Connell Street. Third one's halfway between, also on the quays."

"In other words," I said, "our caller's not one of the local boys who have their knickers in a twist over the value of their houses."

"I wouldn't say so. Going by the times, he's ringing on his way home from the pub. I suppose a Knocknaree fella could drink in town, but it doesn't sound likely, not as a regular thing. I'll have the lads check, to make sure, but for now I'm guessing this is someone whose interest in the motorway is business, not personal. And if I was a betting man, I'd put money on him living somewhere along the quays."

"Our killer's almost definitely local," Cassie said.

Sam nodded. "My boy could've hired a local to do the job, though. That's what I'd have done." Cassie caught my eye: the thought of Sam earnestly toddling off in search of a hit man was irresistible. "When I find out who owns that land, I'll see if any of them have been talking to anyone from Knocknaree."

"How are you getting on with that?" I asked.

"Ah, sure," Sam said cheerfully and vaguely. "I'm working on it."

"Hang on," Cassie said suddenly. "Who does Jessica phone?"

"No one," Sam said, "as far as I can tell," and he patted the papers gently into a stack and took them away.

All that was on the Monday, almost a week after Katy had died. In that week, neither Jonathan nor Margaret Devlin had phoned us to ask how the investigation was going. I wasn't complaining, exactly-some families ring four or five times a day, desperate for answers, and there are few things more excruciating than telling them we have none-but all the same: it was another small unsettling thing, in a case that was already much too full of them.

Rosalind finally came in on Tuesday, at lunchtime. No phone call, no arrangement, just Bernadette informing me with faint disapproval that there was a young woman to see me; but I knew it was her, and the fact that she had shown up out of the blue like that smacked of desperation somehow, of some clandestine urgency. I dropped what I was doing and went downstairs, ignoring the inquiring raised eyebrows from Cassie and Sam.

Rosalind was waiting in Reception. She had an emerald shawl wrapped tightly around her; her face, turned to look out the window, was wistful and faraway. She was too young to know it, but she made a lovely picture: the fall of chestnut curls and the splash of green, poised against the sunlit brick and stone of the courtyard. Block out the defiantly utilitarian lobby, and the scene could have come straight off a Pre-Raphaelite greeting card.

"Rosalind," I said.

She spun from the window, a hand going to her chest. "Oh, Detective Ryan! You startled me… Thank you so much for seeing me."

"Any time," I said. "Come upstairs and we'll talk."

"Are you sure? I don't want to be any trouble. If you're too busy, just tell me and I'll go."

"You're no trouble at all. Can I get you a cup of tea? Coffee?"

"Coffee would be lovely. But do we have to go in there? It's such a lovely day, and I'm a little claustrophobic-I don't like to tell people, but…Couldn't we go outside?"

It wasn't standard procedure; but then, I reasoned, she wasn't a suspect, or even necessarily a witness. "Sure," I said, "just give me a second," and ran upstairs for the coffee. I'd forgotten to ask her how she took it, so I added a little milk and put two sachets of sugar in my pocket, in case.

"Here you go," I said to Rosalind, downstairs. "Shall we find somewhere in the garden?"

She took a sip of coffee and tried to hide a quick little moue of distaste. "I know, it's foul," I said.

"No, no, that's fine-it's just that…well, I don't take milk, usually, but-"

"Oops," I said. "Sorry about that. Want me to get you another one?"

"Oh, no! It's all right, Detective Ryan, honestly-I didn't really need coffee. You have this one. I don't want to put you to any trouble; it's wonderful of you to see me, you mustn't go out of your way…" She was talking too fast, too high and chatty, hands flying, and she held my eyes for too long without blinking, as if she had been hypnotized. She was badly nervous, and trying hard to cover up.

"It's no problem at all," I said gently. "I'll tell you what: let's find somewhere nice to sit, and then I'll get you another cup of coffee. It'll still be foul, but at least it'll be black. How does that sound?" Rosalind smiled up at me gratefully, and for a moment I had a startled sense that this small act of consideration had moved her almost to tears.

We found a bench in the gardens, in the sun; birds were twittering and rustling in the hedges, darting out to wrestle with discarded sandwich crusts. I left Rosalind there and went back up for the coffee. I took my time, to give her a chance to settle down, but when I got back she was still sitting on the edge of the bench, biting her lip and picking the petals off a daisy.

"Thank you," she said, taking the coffee and trying to smile. I sat down beside her. "Detective Ryan, have you…have you found out who killed my sister?"

"Not yet," I said. "But it's early days. I promise you, we're doing absolutely everything we can."

"I know you'll catch him, Detective Ryan. I knew the minute I saw you. I can tell an awful lot about people from first impressions-sometimes it actually scares me, how often I'm right-and I knew right away that you were the person we needed."

She was looking up at me with pure, unblemished faith in her eyes. I was flattered, of course I was, but at the same time, this level of trust made me very uncomfortable. She was so sure, and so desperately vulnerable; and, although you try not to think this way, I knew there was a chance this case would never be solved, and I knew exactly what that would do to her.

"I had a dream about you," Rosalind said, then glanced down, embarrassed. "The night after Katy's funeral. I hadn't slept more than an hour a night since she vanished, you know. I was-oh, I was frantic. But seeing you that day…it reminded me not to give up. That night I dreamed you knocked on our door and told me you'd caught the man who did this. You had him in the police car behind you, and you said he'd never hurt anyone again."