Step Conti picked up warily, and she didn’t blame him. Finding out that your best friend had been at the very least a serial rapist would have made anyone wary. Each phone call from the police so far had revealed a darker and darker truth, and she felt a twist of guilt that she was now in the process of pinning a murder on Alex, too.

‘Step, hi,’ she said. ‘DC Hanson here. I’m sorry to call you on a Friday night, but there’s something we need to check with you. It’s about that night that Alex and the guys gave you the knife. January the nineteenth.’

‘If you’ll just give me a second …’ There was a brief toddler screech in the background. His daughter, she guessed, up later than she was supposed to be. After that came the sound of a closing door. ‘OK,’ Step said. ‘Yes.’

‘I just wanted to know what happened to the knife after you were given it,’ she asked. ‘Did you hold on to it yourself? Or did someone else look after it?’

‘Um … oh,’ Step said. ‘I left it behind the bar. Marc’s brother Charlie owns the club we went to, and he offered to keep hold of it.’

‘Marc’s brother,’ Hanson said. ‘So that’s Charlie Ruskin?’

‘Yes,’ Step confirmed.

‘Does he own any other clubs?’ she asked, trying to make the question sound as if it had no importance at all.

‘Yeah, he has three. We normally go to the one in Southampton but we did an overnighter in Portsmouth for my birthday.’

‘Oh, right,’ she said, aware that her voice sounded not quite right. ‘The one in Southampton, is that Blue Underground, where you were last Friday?’

‘Yes, that’s the one.’

Hanson was aware that she was shivering, and that it had as much to do with the adrenaline that was suddenly coursing through her as it had to do with the cold. She tried to keep her head. To ask all the relevant questions.

‘Did you take it home at the end of the evening? The knife?’

‘No,’ Step told her. ‘Charlie wasn’t around when I left so I got it off him the next day.’

‘That’s great, thanks,’ she said. And then she added, ‘So it couldn’t have ended up with Alex?’

‘No,’ he said, firmly. ‘No, it couldn’t.’

April swung herself to her feet and grabbed her handbag. ‘I’m going to pee and redo my lip gloss. You coming?’

Louise shook her head, determined not to be a tag-along. Not to be needy, anxious Sober Louise any more. ‘I’m good here, thanks.’

But as soon as April was gone, she regretted not going with her. The club turned from a comfortably dim place into a shady, crowded cavern. The men dancing down on the floor took on a predatory shape, and she found herself staring at the closer ones.