‘Who was looking after your kids on Friday night?’ Perez asked. Sandy thought that was a strange place to start.

‘They stayed at my mother’s. Except Neil, who was playing football in Brae with Andy. Why?’ She wasn’t hostile, but she looked at Perez as if he were a bit mad.

‘And you were out with Evie?’

‘Aye, the hen party. A charity pub-crawl. Typical Evie. She couldn’t just get pissed and make a fool of herself, like everyone else. She had to save the world at the same time.’

‘Could you talk me through the evening?’ Perez said. ‘It’s not that I’m accusing anyone, but you might have been witnesses.’

Jen poured coffee. She seemed in no rush to get back to the kitchen. Sandy thought she was one of those competent women who could knock up a good meal in about ten minutes, and who was never flustered.

‘The bus picked us all up in our homes,’ she said. ‘Evie first, and then the rest of us. We started drinking in the Busta House hotel in Brae. We thought we’d better start there because it’s kind of grand and, though Veronica had said it was OK, we didn’t want to seem rowdy in front of their guests. So we just had the one drink, rattling the collecting bucket round the bar, and most of us were still quite sober.’

Perez nodded. ‘And you were all dressed up in pairs?’

‘Aye! Crazy!’

‘How was Evie?’

And it seemed to Sandy that this was the important question and that the others had been to get Jen relaxed and ready to answer.

There was a pause.

‘Was Evie quite herself?’ Perez persisted. ‘Only I heard that she got very drunk, and I wouldn’t have thought that was in character.’

‘It was a pub-crawl,’ the woman said. ‘Of course she got drunk!’

‘But she organized it.’ Perez’s voice was reasonable. ‘I’d have thought she’d have paced it so that she didn’t overdo things. Or had someone thought it would be funny to spike her drinks?’

And that was when Jen started talking, the words spilling out despite herself, as if they’d been building up for days and now some kind of dam had burst. A mixture of relief to be sharing the worry, and guilt that she was betraying her friend. ‘I don’t know what came over her. I think she’d been drinking in the afternoon. I asked if she’d been out with her mates at the office, but she said not. She was wild. I’d never seen her like that before, and I’ve known her for years. She was drinking vodka and she never usually touches spirits. The others thought it was funny. Evie’s usually the one telling us to slow down. But I didn’t like it. I stopped drinking after a bit, so that I could look after her.’