Steve has split his plastic water cup and is folding it into shapes. He says, ‘It could be just that: him trying to fuck us up.’ The ‘us’ is cute – no one’s on any campaign to fuck Steve up – but it gives me a quick ridiculous beat of warmth anyway. ‘I’ve never got that vibe off him either, but. I always got the sense he doesn’t give a monkey’s about us, either way.’

‘Me too. But if he was serious about getting rid of us, that’s exactly the sense we would get. Breslin’s no genius, but he’s been at this a long time. He’s well able to hide what he’s at.’

‘Or,’ Steve says. ‘If the gangster thing pans out . . .’

He leaves it there. The sharp crack of folding plastic jabs me in the ear.

Bent cops exist. Fewer in real life than on the telly, but they’re out there. Everything from the guy squaring a speeding fine in exchange for match tickets, to the guy who’s owned by a gang boss, body and soul.

If a gangster boyfriend killed Aislinn, the first thing he or his pals would do is ring their best bitch-boy and tell him to sort it out. The perfect way to sort it out, no loose ends, no worries, would be charging Rory Fallon and closing the case.

‘Breslin,’ I say. I’ve stopped pacing; stopped breathing, almost. ‘Breslin. You think? Seriously?’

Steve lifts one shoulder.

‘Nah. I don’t see it. He’s all about being the big hero. He wouldn’t be able to handle seeing himself as the bad guys’ pet cop. It’d blow his brain cells.’

Steve says, ‘Breslin would find a way to see himself as the hero, no matter what he did. That’s where he starts: with the idea that he’s the good guy, so whatever he’s doing must be right. Then he works backwards from there to figure out how.’

Which is true, but I never thought about it that way before – I’ve never spent this much time thinking anything about Breslin before. I don’t like the feel it gives me, clamped onto the back of my neck. What Steve’s talking about, it’s not just Breslin who thinks that way; we all do. When you badger a statement out of some traumatised witness, or manipulate a mother into giving evidence that’ll put her own kid in jail, you get to enjoy the buzz of winning without tying yourself in knots over the deeper moral subtleties, because you’re the good guy in this story. Steve is shredding that into something different, something tangled and thorny; dangerous.

He says, ‘And he’s the type they go for. Wife, kids, mortgage . . .’