‘You were right,’ he said, speaking to Baaz, who smoothed the note out between us. ‘The letters printed at either end of the serial number are inconsistent with the serial numbers of the bills known to be in circulation. So, in this respect, you could say that the note is a fake. It looks like … How to explain this?’ He rested the cigarette in the ashtray and scratched his beard. ‘An impossible note. But many bills get printed that are never meant to be circulated. Don’t forget, you can put whatever numbers and letters you like on any plate – whether you work for the Bureau of Engraving’ – he touched his chest lightly with fingertips of his right hand – ‘or not.’

‘But in every other respect the bill is genuine?’ I asked.

‘OK, there is always a margin of error. That, I admit. The tools I have, the software, the microscope … This old man’s eyes! They are good, but I am not the Fed. If I was, I would photograph this bill and blow it up the size of a house and crawl across it on my hands and knees looking for clues. That’s what they do. Really! Crazy, no?’

‘How wide is the margin of error? How sure are you?’

‘In this case,’ he said, ‘let us say that I am sure.’ He smoothed his beard and picked up the bill. ‘Why? Because I have seen this note before.’ I went to speak, but he held his hand up. ‘No! Not this one. But its twin. Exactly the same printing. Same series. Different numbers. And without, uh, “Arkhangel” written on the back, of course.’

‘Where?’ I asked him. ‘Where did you see it?’

‘Here,’ he replied. ‘Hundreds of them were found by our Special Forces, also in Lebanon,’ he explained. ‘During a raid. This time Israel got the blame, though. But it wasn’t us. It was, how do you say … quid pro quo. Our mutual friend asked me to look at them. Interpret them, as you would say.’

‘OK,’ I nodded. ‘But if you didn’t forge them, who did? The Iranians?’

‘No.’ He handed the note back to me and retrieved his cigarette from the ashtray. ‘The Russians, of course.’

He smoked his cigarette and we all considered what he’d said in silence. I lit another Marlboro and tucked the packet and matches back into my jacket.