‘See, though,’ Steve explains, ‘we’re not just trying to take this particular coat off our list. We’re trying to take you off our list. That means we need anything you could’ve worn, not just what you did wear. See what I mean?’

Rory pushes up his glasses to press his fingers into the corners of his eyes. ‘Yes. OK. Whatever you need. I’d rather be there, though – when you’re in my apartment. I don’t like the thought of people . . . Is that all right?’

‘Not a problem,’ Steve says easily. ‘The lads who bring you home can just take a quick look around while they’re at it. We’ll get on that as fast as we can, yeah? Get your prints done and get you out of here, back to your day.’

Rory’s eyes close, against his fingertips. ‘Yes,’ he says. ‘I’d like that very much.’

I toss Rory’s gloves and his coat into evidence bags and head off to send them to Sophie, before he can change his mind. Then I type up his statement, and ignore the squad-room turds ignoring me, while Steve prints off a map so Rory can draw us his route home – as near as he can remember, or wants to – and takes him through his story one more time. I give the two of them as much alone time as we can afford, in case Rory’s still holding a grudge against me, but when I come back into the interview room Steve throws me a minuscule shake of his head: nothing interesting has happened.

‘Here,’ Rory says, pushing the map across the table. He’s looking rough. His lips are parched and the mousy hair is plastered flat to his head, like he’s been running in heat. ‘Is that OK?’

There’s a careful line winding from Stoneybatter to Ranelagh, and a tiny tidy X labelled ‘FLOWERS’ on the quays. ‘That’s great,’ Steve says. ‘Thanks a million.’

‘Have a read of that,’ I say, holding out the statement and a pen. ‘If it’s all correct, initial every page and then sign at the end.’

Rory doesn’t move to take the statement. ‘Do you think . . .’ He catches a long breath. ‘If I hadn’t left when I did. If I’d kept banging on the door, or if I’d called the police, or if I’d broken in. Would I have been able to save her?’

I almost say yes. If he’s not our guy, he’s such a godawful damp weenie, the kind who needs regular slaps across the back of the head just to keep him from vanishing up his own hole, plus he just wasted half our day by being in the wrong place looking guilty as hell. All I have to do is say yes, and he’ll spend the rest of his life whipping himself with a more and more elaborate fantasy where he storms into that cottage in the nick of time and saves Aislinn from a herd of rampaging bikers and they live happily ever after and have 2.4 damp weenie kids. It’s practically irresistible.