I dropped Kush off at the houseboat. The bathroom has a sunken bath so I slipped a bath mat into it and coaxed Kush to clamber inside. He sniffed a bit but then settled down on the mat. He seemed happy enough until I tried to leave and he started barking like crazy. I hope Leah doesn’t mind. I park and turn the engine off, letting the silence surround me for a moment, soothing the kernel of dread that has been creeping up on me during the drive. I stare at the towers looming over me, and feel that pit-of-the-stomach dread increasing with each passing thought. Was I part of putting an innocent man in there? Did the real killer get away, only to kill again? Is Marianne Kleine’s death on me?

The black wolf’s got his nose to the wind, sensing the anxiety, feeding on it, waiting for a chance to strike.

My thoughts are starting to speed up, a tell-tale sign. I wonder about having a quick hit before going in, and even pull out a bag from the glovebox. I stare at it, torn. No. I can do this. I can conquer this feeling on my own. I stash it and reach for the door.

The guy on reception remembers me from last time I’d been here and doesn’t even suspect I may not be on official business. As he leads me down brightly lit and eerily quiet corridors he tells me exactly why my trip will be a wasted one.

‘Don’t think you’re going to get much out of him,’ he says. ‘Guy’s fucked in the head.’

Sometimes I wonder if that doesn’t just sum up the human condition. He motions me into a viewing booth and tells me Klaasen will be brought in shortly. I suddenly find the room seems slightly off centre, like the angles aren’t all straight. My hands are cold now, palms moist. I think of the glovebox. Damn. I should have had a pull. The anxiety’s definitely kicked up a level. In fact, it’s knocking the walls off. My thoughts are speeding up. I try to slow them down to manageable levels.

I don’t know why I’ve come.

To apologize? Or to try and make myself believe he really did kill Muller all those years ago?

It’s time to go. Doing this is only going to feed the black wolf. I stand up just as the door on the other side of the cramped space opens and a man shuffles in: prison PJs, hands cuffed, head down. He seems lost for a moment, then shuffles forward and sits on the chair opposite mine. I’m swimming, treading water. My breathing’s ramping up. I get the weirdest sensation, like I want to laugh. He brings his head up, eyes settling on mine.

I stare at the face in front of me.