The woman behind the glass screen is surprised to see us again, but buzzes us straight through. We find Sargant Prangle at her desk. She unfixes her eyes from her computer screen and blinks a few times before realising we’re standing in front of her.

‘We need to tell you something else,’ I say.

Mum did tell him about the websites, she admits when we’re back in the room with Sargant Prangle and the tape recorder again. Or she didn’t tell him so much as ask advice ‘for a friend’ and he’d worked it out. But of course he’d already known. And before that, he knew about how I’d got the bruise on my face.

I feel a little uncomfortable listening as Mum recounts the details of their meetings. The first few times they’d bumped into each other at the supermarket, the flirtatious coffees and text messages. Like earlier, I try to turn my mind off, to focus on other things.

He’d waited for a catalyst, struck me while I was most vulnerable. Maybe he and Carl had even planned the punch at the party. It seems like years ago now. Hard to believe it’s not even been six months. Then he, ‘Martin’, had set himself up as some kind of confidante, had invaded my home, pretended to offer some kind of support when all along he’d been calling the shots. It was probably him who’d told Alan where I lived, had given him the textbook to drop off. Him who wanted to know about where Dana was yesterday. And it was him who had ordered me to smash that shop window.

Perhaps Mum is picking up on my thoughts. She grows more and more incandescent with rage as she talks more and more about the interest Martin had shown in me, how he’d always ask after me and who I was seeing. He seemed, she says, far more interested in me than in her.

‘This can, of course, only be taken as speculation,’ the Sargant says when Mum’s finished. ‘We’ll follow it up, of course. But all we have is a first name to go on here. That’s the only common factor.’

But it was him. It is him behind this plan, this savage and inhuman plan. And the way that Carl spoke at that meeting, the way he controlled the room. He could only have learnt that from Mr Walters; it had his stamp all over it.

Back on the road home again, Mum is still furious. At herself, mostly. ‘I can’t believe I could have been so stupid. What was I thinking?’

Dana does a good job of calming her. She knows about men, about what they’re capable of saying, of doing. Mum talks to her as if there isn’t a gap of thirty years between them.