I thought again of the photograph I found of her on the first night I slept with Zac. I’d searched for it several times since, without luck. ‘Yes.’

‘Then you know you resemble her. Same height and build – you’re a couple of centimetres taller, but not much. Same colouring, that unusual strawberry blonde hair you both have. Doesn’t that disturb you?’

‘Having a preferred type isn’t a sign that a man’s a psychopath and a murderer.’

‘Holly. I need to ask if Zac has ever done anything to hurt you.’

‘Of course not.’ I tugged Zac’s parka down at the wrists. They were slightly red and swollen, from where he’d pinned them above my head the previous night, one of those fine lines that you sometimes crossed during sex, when you were carried away. ‘But despite the fact you obviously disagree, rather than rescue me from him you want to send me back in.’

‘I’m confident there’s nothing I can say or do right now to keep you away from him. You don’t want to be rescued. So, given that this is where we find ourselves, it would help us a great deal if you would keep an eye out.’

‘No.’

‘You don’t need to do much. We can start small. If you come across any objects of Jane’s, tell us about them in as much detail as you can. Give them to us, if at all possible.’

‘It’s pointless. Not just because I said no and I mean it. Zac doesn’t even have any of her things.’

‘You might still stumble on something. We’d like to know of any communications Zac makes, especially if they are connected in any way to Jane. Who are his contacts? How does he get in touch with them? Email? Text? Phone? Laptop? Does he have any social media accounts? Maybe under a user name that people wouldn’t link to him? What trips does he make? If he ever happens to leave a device powered on you might be able to look. See if you can guess his password. Pay attention to where he’s going, who he’s meeting, if anyone ever visits him at work . . .’

‘Those are disgusting things to do to someone you care about, someone who’s trusted you and let you into their life.’

‘Do what you are comfortable with, then. What you can. You understand Zac. You’re intimate with him. You see the ins and outs of how he operates in ways we can’t.’

‘The answer’s no.’

‘It won’t kill you to think about it, and to be gently watchful while you do.’

‘Again . . . no.’

‘Let me ask you something.’

‘What?’

‘Did you ever tell Zac you tried to join us?’