It’s a great idea, deeply sensible. I shared an afternoon with Pavel’s son a couple of months ago, and we exchanged phone numbers before we parted. My call finds Ivan at home in Perth, nursing a glass of Shiraz after a rugged day with the new intake of first-year students at the university where he teaches. He seems genuinely glad to hear me and after a brief catch-up, I tell him about the Beeb’s interest in whatever his dad might have been hiding. As far as I know, probate on Pavel’s estate has yet to be finalized and Ivan is the chief beneficiary. This – if I find the mystery file – could be very good news.

‘Do I smell money?’ Ivan is laughing.

‘Lots, if I look under the right stone.’

‘Then do your worst. Fifty per cent? Half and half? Does that sound fair?’

I tell him he’s crazy, and suggest he opens another bottle. With his blessing, I’ll put Pavel’s MacBook in hands I can trust, someone who knows what they’re doing, and report back. This, he says, sounds like a plan. Go ahead. Do your worst. Then he’s gone.

It’s at this point that I remember Christianne telling me about McFaul’s cyber talents. Next door lives a man who wrote his own computer programme to make life just a little sweeter in the minefields. Surely, he could take a look at Pavel’s machine?

Minutes later, I’m standing at McFaul’s front door. I’ve wrapped Pavel’s MacBook in a Waitrose bag against the rain and I’m beginning to think that McFaul might be out when the door opens. McFaul, for some reason, has worked up a light sweat.

‘Come in.’ He’s looking at the Waitrose bag. ‘What’s that?’

I tell him it doesn’t matter, not yet. First, I want to know the latest about Christianne. Has he been in touch with that nice Inspector Bevan?

‘Yeah. He phoned me on the landline earlier. They’ve got more hands to the pump. Has anyone mentioned the Force Support Group? Bevan’s like a pig in shit. He says he’s reorganizing the search the way he always wanted. I told him there was no point, but these people never listen. He thinks she’s out there. And he’s sure he’s gonna find her. Does that sound like optimism? Or early dementia?’

He shakes his head. We’re still standing in the hall and through the open door I can see the big lounge at the front of the property. Last time I took a look, it reminded me of an auction house before they get everything sorted, a jumble of mismatched items dumped in the hope of a sale. Now, the battered furniture has been tidied into a single corner of the room, chairs piled on chairs, cardboard boxes brimming with stuff that nobody will ever buy.