Illmann nodded by way of acknowledgement, and carried on with his perfect roll-up. He was a slight man with thin, dark hair, rimless glasses and a small chin beard. He finished licking the paper and poked the roll-up into his mouth, as good as any machine-made cigarette. I marvelled quietly. Medical brilliance counted for nothing beside this kind of subtle dexterity.

‘Professor Illmann will take us through his findings after Kriminalassistant Korsch has read the relevant case note.’ I nodded at the dark, stocky young man sitting opposite me. There was something artificial about his face, as if it had been made up for him by one of the police artists from Sipo Technical Services, with three definite features and very little else: eyebrows joined in the middle and perched on his overhanging brows like a falcon preparing for flight; a wizard’s long, crafty chin; and a small, Fairbanks-style moustache. Korsch cleared his throat and began speaking in a voice that was an octave higher than I was expecting.

‘Brigitte Hartmann,’ he read. ‘Aged fifteen, of German parents. Disappeared 23 May 1938. Body found in a potato sack on an allotment in Siesdorf, 10 June. She lived with her parents on the Britz Housing Estate, south of Neukölln, and had walked from her home to catch the U-Bahn at Par-chimerallee. She was going to visit her aunt in Reinickdorf. The aunt was supposed to meet her at Holzhauser Strasse station, only Brigitte never arrived. The station master at Parchimer didn’t remember her getting on the train, but said that he’d had a night on the beer and probably wouldn’t have remembered anyway.’ This drew a guffaw from along the table.

‘Drunken bastard,’ snorted Hans Lobbes.

‘This is one of the two girls who have since been buried,’ said Illmann quietly. ‘I don’t think there’s anything I can add to the findings of the autopsy there. You may proceed, Herr Korsch.’

‘Christiane Schulz. Aged sixteen, of German parents. Disappeared 8 June 1938. Body found 2 July, in a tramway tunnel that connects Treptower Park on the righthand bank of the Spree, with the village of Stralau on the other. Half way along the tunnel there’s a maintenance point, little more than a recessed archway. That’s where the trackman found her body, wrapped in an old tarpaulin.