‘That’s right,’ said Sergeant Murphy. ‘Like I say, most of it is hours and hours of nothing at all. But you can see Justice Quinn taking his Jaguar out of his garage every morning and driving off, and then driving back again in the evening and putting it away. You can tell that it’s his pride and joy, because he always puts it away, out of the rain, except when he fetches it out on Saturday and gives it a wash and a polish. The way he does it, it wouldn’t surprise you if he gave it a kiss.’

Katie said, ‘I don’t see him coming out of his front door, so there must be access to the garage from inside the house.’

‘Now and again you see his wife coming out and driving off in her Lexus. There, see – there she goes. Each time she’s back about two or three hours later so she’s probably been shopping or out for lunch. The only times you see Justice Quinn himself is at the weekends, when he comes out to sign a letter for the postman or take a sconce at his front garden. But now let’s fast forward to that morning when he was murdered.’

The garda ran through the footage until she reached the day that Justice Quinn had died. As usual, the garage door was raised, and Justice Quinn’s white Jaguar reversed out on to the drive. This time, though, the garage door remained open, and the Jaguar stopped on the drive with its engine running. Orla came out of the front door in a long white towelling dressing gown and a paisley headscarf and walked around the front of the car. As she did so, the driver’s window was let down, and it could be seen that the driver was saying something to Orla and gesticulating with his right hand. Even though she now had her back to the camera, Orla seemed to be arguing with him, because she was raising both hands and making chopping gestures.

Katie said, ‘Maura – could you pause it, please. No, back a bit. Back a little more. That’s it, there.’

She leaned closer to the screen, although she had already seen what she needed to see. The driver of the Jaguar wasn’t Garrett. It was a bald, pouchy-cheeked man with glasses, wearing what looked like an olive shawl-neck sweater. He reminded Katie of some comedian that she had never found funny.

‘That’s obviously not Justice Quinn,’ said Sergeant Murphy. ‘Do you reck him at all?’

Katie slowly shook her head. ‘I’ve never seen him before. He looks like a bit of a gouger, though, don’t you think? And how did he get into the house without the CCTV picking him up?’

‘Maybe there’s a back door. Maybe he’d been staying there for days. Who knows?’

‘So where’s Justice Quinn?’