‘No. She had the kid and, obviously, I couldn’t be there if he was.’

That didn’t make any sense. ‘Wasn’t Sam with his dad that night, though?’

‘He was meant to be, but Alex cancelled.’ As he said the name, I heard bitterness in his voice. ‘It happened a lot. She’d have to change plans at the last minute, because his dad flaked out. And I can’t get away all that much.’ He looked at me. ‘Anna assumed he was seeing you those nights, I have to say.’

‘No . . . well, not that night. He told me he had Sam, so we didn’t see each other. You didn’t contact the police to tell them this?’

‘No,’ he said, shamefaced. ‘I was afraid. Thought they might suspect me, and my wife would find out – and I’ve no alibi, since she was away. I just stayed home, had an oven pizza.’

How could I say he was wrong not to contact the police? I knew from bitter experience that being innocent was no protection. ‘So – Alex told me he had Sam, and Anna told you she did. Question is, who was lying?’

‘Well. Obviously, I’m going to say Alex.’

‘But you didn’t know Anna all that well, right? She could have had other secrets.’

‘How long have you known Alex?’ he countered.

‘Only a few months,’ I admitted.

‘You trust him?’

‘I . . . I did.’ But he hadn’t told me about Stacey Donner. That he too had once been a murder suspect. ‘I’m sorry, Ciaran, but when Anna came for me that day at the shop, I got the impression she wanted Alex back. That she was warning me away from him.’

He frowned. He had a faint moustache of latte foam on his lip and I felt a pang suddenly. He was a nice man, attractive, and I hoped Anna had been happy with him, in the little time she’d had. I imagined his marriage wasn’t that successful, if he was having an affair. How much sadness there was, hidden in everyone’s life.

‘No, that can’t be right. She definitely didn’t want him back. Things were pretty bitter between them.’

But that was often the way with divorcing couples; it didn’t mean there wasn’t love left. Quite the opposite, in fact.

‘She told you about the fight with me?’

‘Yeah. She was kind of ashamed, to be honest. I think she was just having a bad day, with the custody battle, and she saw you there and lost her temper.’

‘The custody battle?’

‘You didn’t know? Alex was trying to get full custody of Sam. Crazy, really, with all the hours he works, but some men will do that, just to spite the wife.’