Matt pauses, keeping his grip on Tim’s hood, and looks at him. There is no longer any trace of yellow in Tim’s eyes. For a split second Matt feels a final wave of doubt, but then he remembers the missing teenager on Rutmoor and the stories of decapitated dogs in Southampton; he remembers the failed abduction attempt in Christchurch – he actually managed to track down the parents of the eight-year-old boy who was nearly taken and arrange to speak to him, and the kid had given him an almost spookily accurate description of Tim – and he remembers the twin girls. Yes, they’re the ones he thinks of most. The drowned twin girls. The papers didn’t publish a description of the bodies, but Matt read the police report. He doesn’t even want to think about how much those little girls suffered before they died.

‘It’s not my fault,’ Tim says, and for a moment Matt thinks he’s read his mind. ‘It’s not my fault Matt, you have to understand that, please. He’s in me, Matt. I don’t want to be like this but he’s fucking in me.’

He kneels there in the river, water dripping down his face to mix with the snot and tears and his fringe hanging in his eyes, and for a second Matt remembers the younger Tim. The quiet, 13-year-old boy who walked in his father’s shadow on that long-ago weekend. The tears sting his eyes so suddenly they take him by surprise.

‘You have to help me, Matt,’ Tim pleads. ‘Help me, you have to help me get rid of him. You have to help me.’

Matt shuts his eyes against the tears, opens them, then puts his hand on the back of Tim’s head.

‘Okay,’ he says. His voice cracks, but only a little. ‘Okay, I’ll help you.’

He tightens his grip and shoves Tim’s head under the water. James goes tense and tightens his own hold on Tim’s arm. He doesn’t look at Matt. Tim’s body thrashes back and forth in the water. Matt has to shift his weight a couple of times and at one point he thinks he’s going to lose his balance, but he holds on.

He can hear Tim’s garbled screams coming from beneath the water, but they’re distant. They’ll stop soon.

You have to do this, he thinks. And not just for the other children he’ll hurt. You have to do it for that boy who disappeared last year. You have to do it for the Plumber twins. You have to do it for Tom and for Gary, and for all the others who aren’t here anymore.