He wouldn’t have wasted time on losing the head when he realised what he’d done, not McCann. Ds are experts at slamming the emotions away for later, when we can afford them. As soon as he knew Aislinn was dead or on her way there, he would have taken off his shoes so as not to leave prints, grabbed a handful of kitchen roll and started wiping down every place where Breslin could have left a fingerprint. Turned the cooker off, because God forbid it should set off the smoke alarm before he was done and far away. Listened to the doorbell and the knocking, to Aislinn’s phone chirping and ringing as Rory tried to find her, and stayed out of eyeshot of the windows. When he was done, he would have scuffed out any shoeprints he’d left on the way in, stuffed the kitchen roll in his pocket to dump in a bin on the way home, and slipped out the back door. Thirty-five to fifty-five minutes: plenty of time.

‘How come you didn’t tell us about this on Sunday?’ Steve asks.

‘Because . . .’ Rory rubs at his mouth. ‘OK. You see, I’d seen him before. Twice. In Stoneybatter. The first time was an evening maybe three weeks ago – I was looking for my chance to go down the laneway, and he was right at the top of it lighting a cigarette, so I had to walk around the block and try again. I was across the road from him, that time, so he might not have noticed me; I only noticed him because he was in my way. But the second time – I think about ten days ago – I passed right by him on Astrid Road when I was heading home, and we made eye contact. There was a good chance he’d remember me, if he had any memory at all for faces. I knew if I told you about seeing him on Saturday, you’d try to track him down – and if you did, he’d tell you about seeing me before, and then you’d know I’d been . . . I was hardly going to tell you about him. I was praying you wouldn’t find the guy.’

What the hell? hovers in the air between me and Steve. What was McCann doing, hanging around Aislinn’s gaff for weeks on end?

Rory takes the second of silence as disbelief. ‘I was scared! “Oh, by the way, Detective, I was spending half my evenings wandering around Stoneybatter peering in a woman’s window, and while I was at it I happened to notice another guy who might have been doing the same kind of thing, so you should really look at him . . .” I would have had to be insane to come out with that. Look what happened when you did find out.’