Reilly was a year behind me in training college. He’s a lot less useful than Kellegher, but I’m guessing he’ll make the squad sooner, just going by how beautifully he’d fit in with this shower. ‘Kellegher can finish that up,’ I say. ‘With twenty minutes to spare, Fallon could have got, say, half a mile off the route he gave us. Do a half-mile radius, to start with. See you later.’

Reilly’s chin moves and he gives me a piggy stare, but he heaves himself out of his chair and starts disentangling his coat. ‘Kellegher,’ I say. ‘Tell me you’ve got some good news to go with that.’

‘Some, yeah. We’ve picked up Fallon in four locations between Stoneybatter and Ranelagh, on his way home. I’ve mapped them up there.’ Kellegher nods at a new map on the whiteboard, complete with X’s and arrows and a halo of grainy time-stamped photos. ‘They’re consistent with his statement.’

I take a look. The slight guy in the black overcoat has his head down, against the rain and his bad evening, but it’s Rory, all right. In the earliest shot, on the northside quays, there’s a smashed-looking bunch of flowers sticking out of his armpit; by the time he gets across the river into Temple Bar, it’s gone.

‘Do we ever get a look at his hands?’ I ask.

‘Nah. In his pockets.’

‘Meehan,’ I say. ‘I need you to time Fallon’s route home. I want to see if he could have taken a detour anywhere along the way – gone off to ditch his gloves, or called in to a mate. Kellegher: what pace is he going on the CCTV?’

‘Brisk, I’d call it,’ Kellegher says, considering the Temple Bar shot, where Rory’s been shouldered off the pavement by a howling stag do wearing fake tits and waving beer cans. ‘Not jogging or anything, but he wanted to get home, all right. Yeah: brisk.’

‘You heard the man,’ I tell Meehan. ‘Viking Gardens to the Wayward Bookshop, nice and brisk, and record the times when you hit the places where the CCTV caught Rory.’

‘I’m going to get fit on this one,’ Meehan says, pushing his chair back.

‘Make it brisk enough and you might beat the rain,’ I say. ‘Thanks. Kellegher, how much of that footage have you got left to watch?’

‘Not a lot.’

‘When you’re done, go have chats with the people who were at the book launch where Aislinn and Rory met. See how it looked: whether one of them was doing the chasing, whether either of them said anything interesting about the other, anything you can pick up. Yeah?’