“Motive? Why would he intercept her to begin with, never mind argue with her?”

“Unknown. Everyone says Kevin was pretty attached to Francis, so it could be he didn’t want Rose taking him away. Or it could be sexual jealousy-he was just at the age to cope really badly with that. She was gorgeous, by all accounts. Maybe she’d turned Kevin down, or maybe they’d had something on the side-” Stephen suddenly remembered who he was talking to. He blushed, shut up and shot me an apprehensive look.

I remember Rosie, Kevin had said. That hair and that laugh, and the way she walked… I said, “The age gap was a little wide for that-we’re talking fifteen and nineteen, remember. But he could have fancied her, all right. Keep going.”

“Well. The motive doesn’t even have to be anything big; I mean, as far as we know, it’s not like he was planning on killing her. It looks more like it just happened. When he realizes she’s dead, he drags her body to the basement-unless they’re down there already-and puts her under the concrete. He was strong for his age; he’d worked part-time on a building site, that summer, fetching and carrying. He would’ve been able for it.” Another quick glance. I picked ham out of a back tooth and watched him blandly.

“At some stage in all this, Kevin finds the note Rose was going to leave for her family, and he realizes he can use it to his advantage. He stashes the first page and leaves the second where it is. The idea is, if Francis leaves anyway, everyone will basically tumble to the original plan: the two of them have gone off together, and the note’s for her parents. If Francis ends up going home when Rose doesn’t show up, or if he gets in touch with his family at some stage, everyone will think the note was for him and she’s gone off on her own.”

“And for twenty-two years,” I said, “that’s exactly what happens.”

“Yeah. Then Rose’s body turns up, we start investigating, and Kevin panics. According to everyone we’ve talked to, he was pretty stressed out the last couple of days, and getting worse. Finally he can’t take the tension any more. He digs out the first page of the note from wherever he’s been keeping it all this time, he spends one last evening with his family, and then he goes back to the place where he killed Rose and… Well.”

“He says his prayers and takes a header out the top-floor window. And justice is served.”

“More or less, I guess. Yeah.” Stephen watched me covertly, over his coffee, to see if he had pissed me off.

I said, “Well done, Detective. Clear, concise and objective.” Stephen let out a quick breath of relief, like he was coming out of an oral exam, and dove into his sandwich. “How long do you think we’ve got before that turns into the official Gospel according to Kennedy, and both cases get closed?”

He shook his head. “A few days, maybe? He hasn’t sent the file upstairs yet; we’re still gathering evidence. He’s thorough, Detective Kennedy is. I mean, I know he has his theory, but it’s not like he’s just slapping it onto the case and throwing the whole thing away. He’s talking like we-me and the other floaters-we’ll be staying with Murder for the rest of the week, anyway.”

Which meant that, basically, I had about three days. Nobody likes going backwards. Once this case was officially closed out, I would need to come up with notarized video footage of someone else committing both murders before anyone would reopen it. “I’m sure that’ll be a blast,” I said. “What do you, personally, think of Detective Kennedy’s theory?”

That caught Stephen off guard. It took him a second to get his mouthful under control. “Me?”

“You, sunny Jim. I already know how Scorcher works. Like I told you before, I’m interested in what you’ve got to offer. Apart from your mad typing skills.”

He shrugged. “It’s not my job to-”

“Yeah, it is. I’m asking you; that makes it your job. Does his theory float your boat?”

Stephen shoved more sandwich in his mouth, to give himself time to think. He was watching his plate, keeping his eyes invisible. I said, “Yep, Stevie, you do indeed need to bear in mind that I could be biased as all hell, or crazed with grief, or just plain crazy to start with, and any or all of those could make me a very bad person to share your innermost thoughts with. But all the same, I’m betting this isn’t the first time it’s crossed your mind that Detective Kennedy might just be wrong.”

He said, “It’s occurred to me.”

“Of course it has. If it hadn’t, you’d be an idiot. Has it occurred to anyone else on your team?”

“Not that they’ve mentioned.”

“And they won’t. They’ve all thought about it, because they’re not idiots either, but they’re keeping their mouths shut because they’re terrified of getting on Scorchie’s bad side.” I leaned in across the table, close enough that he had to look up. “That leaves you, Detective Moran. You and me. If the guy who killed Rose Daly is still out there, no one’s going after him except the two of us. Are you starting to see just why our little game is ethically OK?”

After a moment Stephen said, “I guess.”

“It’s ethically just peachy all over, because your primary responsibility here isn’t to Detective Kennedy-or to me, come to that. It’s to Rose Daly and Kevin Mackey. We’re all they’ve got. So quit faffing about like a virgin clutching her knickers, and tell me what you think of Detective Kennedy’s theory.”

Stephen said, simply, “I’m not mad about it.”

“Why not?”

“I don’t mind the holes-no known motive, not sure how Kevin found out about the elopement, all that stuff. You’d expect gaps like that, after this long. What’s bothering me is the print results.”

I had been wondering if he would spot that. “What about them?”

He licked mayo off his thumb and held it up. “First off, the unknowns on the outside of the suitcase. They could be nothing, but if this were my investigation, I’d want to identify them before I closed the case out.”

I was pretty sure who had left those unknowns, but I didn’t feel like sharing. I said, “So would I. Anything else?”

“Yeah. The other thing is, right”-a finger went up-“why no prints on the first page of the note? Wiping the second page makes sense: if anyone starts getting suspicious and reports Rose missing, Kevin doesn’t want the cops finding his prints on her good-bye letter. But the first page? He takes it out from wherever he’s been keeping it all this time, he’s planning to use it as a suicide note and a confession, right, but he wipes it clean and uses gloves to stick it in his pocket? In case what, someone connects it to him?”

“And what does Detective Kennedy have to say about that?”

“He says minor anomaly, no biggie, every case has them. Kevin wipes both pages that first night, hides the first one away, when he takes it back out he doesn’t leave prints-people don’t always. Which is true enough, except… We’re talking about someone who’s about to kill himself. Someone who’s basically confessing to murder. I don’t care how cool you are, you’re going to be sweating like a motherf-like mad. And when you sweat, you leave prints.” Stephen shook his head. “That page should have prints,” he said, “end of story,” and he went back to demolishing his sandwich.

I said, “Just for fun, let’s try something. Let’s assume for a moment that my old friend Detective Kennedy is off base for once, and Kevin Mackey didn’t kill Rose Daly. Then what’ve we got?”

Stephen watched me. He asked, “Are we assuming Kevin was murdered too?”

“You tell me.”

“If he didn’t wipe off that note and put it in his own pocket, someone else did it for him. I’m going with murder.”

I felt that sudden, treacherous flood of affection rush through me again. I almost got the kid in a headlock and tousled his hair. “Works for me,” I said. “And what do we know about the murderer?”

“We’re thinking it’s the one person?”