Robin continues. ‘We got back in touch with Lisa, your now ex-girlfriend, I believe? And once we explained that making a false statement to the police can come with a prison sentence, she was keen to put us straight. You weren’t with her Monday night, Kal. You left work at three, and then where did you go?’

No response.

Robin glances at Freya, and she opens the lid of the laptop. ‘We know you would have seen the bruises on Amy’s face on the night of your party,’ Robin says. ‘But what you don’t know is how she got them.’

Kal’s head snaps up. Robin knows he has his attention. Freya turns the laptop to face him, and now Robin presses play on the video, winding it forward to the part of the tape he needs.

At first, Kal seems confused. He glances at Robin. ‘What is this?’ he asks.

‘For the benefit of the video, exhibit Five B. This is a video camera, placed by Jonathan Miller in the living room of his own house. We believe it was put there so that Jonathan could record Amy attacking him.’

‘Amy attacking Jonathan?’ Kal says. His forehead creases.

‘Yes. We know they’d had run-ins in the past. Police had been called, Kal. Amy had been beating Jonathan.’

‘No, no, you’ve got it the wrong way round. I’ve seen the marks on Amy’s face. He was beating her.’

‘No, he wasn’t,’ Robin says. ‘Watch the tape.’

They all stare at the video as Robin presses play. Robin knows what must be going through Kal’s head, the same as Robin and Freya thought when they first saw it. The video is bonkers, almost unbelievable if it wasn’t there in black and white.

Kal watches as Amy stands in the middle of her living room. She’s still, thinking. Then she walks to the open door, between the living room and the hallway. She stands with her feet either side of the door, her hands gripping the handles on each side. And then rams her head hard against the edge.

Kal gasps. The force of the impact makes Amy reel slightly, step backwards from the door. Then she steps forward and does it again. This time her hands go up and she tentatively prods with a finger at her forehead, then walks to the mirror on the other side of the room and looks at it, poking gently.

Kal looks at the video, then back at Robin.

‘She did it to herself?’ he asks, disbelievingly.

‘It seems that way,’ Robin says.

‘But why?’

‘We’re hoping you’ll be able to tell us that.’

Kal reaches forward, winds the video back, then presses play. They all watch the bizarre display again.

‘But she said…’ he mutters. He shakes his head. ‘This can’t be right.’