We cross the bridge on the tree-lined Spaklerweg. An old man shuffles through his own gravitational field, twice as strong as our own. A kid on a scooter is nearly sucked into his orbit as he goes past. Ahead and to the left the Bijlmerbajes prison’s six dismal towers poke the heavy sky and ten minutes later we’re parked by an anonymous concrete building with a corrugated-iron roof painted bright red. Amongst the anonymous cars parked there is a silver-grey Maserati with red-leather seats.

A man’s leaning against the wall next to the only door having a conversation on his phone. ‘I swear, if he makes me work on that again I’m going to walk. I didn’t do a fucking degree to end up doing this kind of menial shit.’ He listens for a few moments before speaking again. ‘No, seriously, I think I’m going to hand in my notice. Let’s see how that old prick gets on without me.’ His eyes flick towards us as we pass, before he dives back into his rant.

Inside, the receptionist has never had anything so exciting as the police turn up. Soon we’re being ushered through an open-plan office towards a door in the far wall, leaving a trail of intrigue in our wake. Beyond it, we discover, is a corner office which has no windows, no ventilation, and no one inside. The receptionist promises that Sven Hertogs will be there shortly. You can just tell she’s itching to rush around and tell everyone that we’re here. Shortly after, a man steps in, looks at us as if in surprise, then sits down behind his desk. He’s fifties, slightly overweight, and is wearing a shirt which has seen better days. As has his face, which is liver-spotted to quite an alarming degree.

‘You’re the police, are you?’ he asks somewhat redundantly.

‘A man of true perception,’ Vermeer says, flashing her badge. ‘He’s with me,’ she adds, jerking a thumb in my direction.

‘I’m with her,’ I say, jerking a finger back.

The man looks between us, like a marriage counsellor facing his most daunting challenge yet. His tongue swipes his lips.

‘Sven Hertogs. So what’s this about?’ He addresses himself to Vermeer.

‘He’ll tell you,’ she says, and I wonder about the wine broker soon-to-be ex.

Hertogs turns to me and I lay out exactly what this is about. He listens, fiddling with his nose as if we can’t see what he’s up to. When I’ve finished he says, ‘I’m not sure how I can help. I can’t give out the volunteers’ details without our client’s permission. Data protection.’

I’m about to tell him that I don’t much care for data protection but Vermeer beats me to it.