McCann shakes his head. ‘Nah. I didn’t think that way. Not at first. I just . . . I loved being with her. Nothing more than that; I never thought of doing more than that. Just seeing her listen to my stories like they mattered. It reminded me of how I used to feel about the job, way back when. The look on her face: when I pulled a good case, I used to feel like that. Like what I did changed things.’

I risk a glance at the gaffer. His face is steady; the shadows of wrinkles and eye sockets turn it unreadable.

‘OK,’ Steve says, keeping the scepticism level well below bitchy. ‘So how did that change?’

‘One night,’ McCann says. He brushes a hand over his cheek, like something fine and cobwebby is catching at him. ‘One night. August. Aislinn said some guy had chatted her up at her evening class. Just in passing, she mentioned it – she wasn’t into him, she’d turned him down. But that was when it hit me: a girl like that, of course she’s going to want a fella. Not just someone for picnics and talk; a man who loves her. A man in her bed. Hit me like a ton of bricks, because I knew once she got him, I’d be gone.’

She made him think it was his idea, Lucy said. She did a good job of it.

‘And then I thought: why not me? Why not? We were loving each other’s company, couldn’t get enough. There was chemistry there – even I could tell that. The way she looked at me, the way her breathing went when we accidentally got close— There was something.’

A sharp glance at me and Steve. That faint stinging red has come up on his cheekbones again. ‘Probably it sounds pathetic to you: just a middle-aged fool head over heels for some young one, oldest story in the world. You weren’t there.’

Every murderer says that to us, sooner or later. You weren’t there. You don’t understand. There’s a small dry chip of silence while no one points that out.

I say, ‘It was that easy? You said, “Hey, let’s give it a go,” and Aislinn said, “Sure, why not?” ’

McCann shakes his head heavily. ‘I don’t know how I made it happen. You two, you keep talking like she hunted me down, but it wasn’t— She didn’t want to be some homewrecker. It took me a while to convince her she was doing no harm that hadn’t been done years ago. When I finally, when we finally . . . that was when I realised: she honest to God cared about me. She . . . It . . .’ A quick involuntary catch of breath. ‘That blew me away. Just blew me away.’