Müller sighed. ‘You’ve lost me, I’m afraid, Jonas. Do I really need to know all this detail of how the code was constructed and how you deciphered it?’

For a moment, under the strange red lighting, Schmidt looked slightly hurt. Then he shrugged. ‘No, Comrade Hauptmann. You’re quite correct. Perhaps I was showing off. You simply need to know what the documents say, and I’m afraid they make for pretty grim reading.’

‘In what respect?’

‘Widespread doping of children, presumably to increase their sporting prowess and performance. The documents – once I’d managed to crack the cipher – show the percentages of which drugs or hormonal supplements have been administered to which children. There’s also a rather chilling appendix listing the noted side-effects. And we’re not just talking about post-pubertal children. Some of the pupils here are aged under ten. None as young as your twins, but even so, if I was you, I would be taking steps to remove Johannes and Jannika as soon as possible, Comrade Hauptmann.’

Under the red control light of the dark room, Müller knew her facial colour wouldn’t have changed obviously to Schmidt. Under normal lighting, he’d have seen her face had gone deathly pale. She’d expected something bad – but not this bad. ‘You’d better fill me in on some of the details, then, please, Jonas.’

Schmidt started to reel off a list of chemicals, and percentages or dosages in milligrams. The names flew over Müller’s head in a bit of a blur – all she could think about was Jannika and Johannes, and how she’d let them down by allowing them to go to the special boarding school in the first place. There was no question but that, at the first opportunity, she would be removing them. If it meant leaving her job, so be it. She had been on the point of quitting so many times. She tried to bring her focus back to what Schmidt was saying.

‘By far the most prevalent drug seems to be Dehydrochloromethyltestosterone, 4-chlor-1-dehydro-17α-methyl-testosterone, Comrade Hauptmann.’

‘That just sounds like a lot of scientific gobbledegook, Jonas. What does it actually mean?’

‘Its non-scientific name is Oral Turinabol – it’s an androgenic-anabolic steroid, made by VEB Jenapharm in Jena. It increases muscle strength, aggressiveness, that sort of thing.’

‘So for male athletes?’

‘From what I know of it, that’s how it was first used. But these documents make it clear it’s being administered to girls too. And as you can imagine, the side effects are pretty horrific.’

‘Such as?’