‘Yeah?’ Steve says, pointing at himself.

He looks like his mammy spit-shined him for Mass, but he plays that up on purpose. You use what you’ve got, and what Steve’s got is that your parents would be delighted if you brought him home. ‘Have to do,’ I say, readjusting the mirror. ‘Let’s go.’

I hit the pedal hard and let the Kadett pretend it’s a real car while it gets us out of there. I get a sudden nasty feeling like the trees behind us have snapped together and come down, with a silent roar and a smash of branches, onto the spot where we were parked.

Lucy Riordan lives in one of those tall old terraced houses split into flats. A lot of those are shitholes, but hers looks OK: the front garden’s been weeded, the window-frames have been painted in the last decade, and there are six bells by the door instead of a dozen, meaning the landlord isn’t jamming people into nine-foot-square bedsits and making them all share a jacks.

It takes two rings before Lucy answers the intercom, in a voice coated with sleep. ‘’Lo?’

Steve says, ‘Lucy Riordan?’

‘Who’s this?’

‘Detective Garda Stephen Moran. Could we have a word?’

A long second. Then Lucy says, and the sleep’s fallen off her voice, ‘I’ll be down in a minute.’

She opens the door fast and wide awake. She’s short and fit, the kind of fit you get from life, not from the gym – she wears it like it’s owned, not rented. Cropped platinum hair with a long sweep of fringe falling in her face – pale face with clean quick features, smudges of last night’s mascara. She’s wearing a black hoodie, paint-splashed black combats, nothing on her feet, a lot of silver ear jewellery and what looks to me like a fair-sized hangover. She has bugger-all in common with Aislinn Murray, or with what I was expecting.

We have our IDs out and ready. ‘I’m Detective Garda Stephen Moran,’ Steve says, ‘and this is my partner, Detective Garda Antoinette Conway.’ And he pauses. You always leave a gap there.

Lucy doesn’t even look at the IDs. She says, sharp, ‘Is it Aislinn?’ Which is why you leave the gap: it’s unbelievable what people will spill into it.

Steve says, ‘Could we come in for a few minutes?’

She looks at the IDs then; takes her time checking them out, or making some decision. Then: ‘Yeah,’ she says. ‘OK. Come in.’ And she turns and heads up the stairs.

Her flat is on the first floor and I was right, it’s decent: a small sitting room with a kitchenette to one side and two doors leading off the others, for the bedroom and the jacks. She had people over last night – empty cans on the coffee table and under it, thick layer of smoke in the air – but even before that, this place was nothing like Aislinn’s. The curtains are made out of old postcards sewn together with twine, the furniture is a banged-up wooden coffee table and a couple of lopsided sofas covered in Mexican-looking woven throws, and there are four 1970s phones and a stuffed fox on top of a coil of cable beside the telly. Nobody ordered this place through an app.