‘Gentlemen, here I’d like to introduce you all to Frau Kalau vom Hofe. I say “Frau”, as she’s not allowed to call herself a doctor, although she is one, because she is very evidently a woman, and we all know, don’t we, that a woman’s place is in the home, producing recruits for the Party, and cooking the old man’s dinner. She is in fact a psychotherapist, and is an acknowledged expert on that unfathomable little mystery that we refer to as the Criminal Mind.’

My eyes looked and licked at the creamy woman who sat at the far end of the table. She wore a magnolia skirt and a white marocain blouse, and her fair hair was pinned up in a tight bun at the back of her finely sculpted head. She smiled at my introduction and took a file out of her briefcase and opened it in front of her.

‘When Josef Kahn was a child,’ she said, ‘he contracted acute encephalitis lethargica, which occurred in epidemic form among children in Western Europe between 1915 and 1926. This produced a gross change in his personality. After the acute phase of the illness, children may become increasingly restless, irritable, aggressive even, and appear to lose all moral sense. They beg, steal, lie and are often cruel. They talk incessantly and become unmanageable at school and at home. Abnormal sexual curiosity and sexual problems are often observed. Post-encephalitic adolescents sometimes show certain features of this syndrome, especially the lack of sexual restraint, and this is certainly true in Josef Kahn’s case. He is also developing Parkinsonism, which will result in his increased physical debilitation.’

Count von der Schulenberg yawned and looked at his wristwatch. But the doctor was not deterred. Instead she seemed to find his bad manners amusing.

‘Despite his apparent criminality,’ she said, ‘I do not think that Josef killed any of these girls. Having discussed the forensic evidence with Professor Illmann, I am of the opinion that these killings show a level of premeditation of which Kahn is simply incapable. Kahn is capable only of the kind of frenzied murder that would have had him leave the victim where she fell.’