Gottfried sat back. ‘Quite impossible,’ he said, and Carla had a feeling he was telling the truth. ‘That is definitely not happening.’ He sounded relieved.

Werner looked as if he had run out of questions, but Carla was not satisfied. She wondered why Gottfried seemed so happy about the assurance he had just given. Was it because he was concealing something worse?

She was struck by a possibility so appalling that she could hardly contemplate it.

Gottfried said: ‘Well, if that’s all . . .’

Carla said: ‘You’re very sure, sir, that they were not killed by an experimental therapy that went wrong?’

‘Very sure.’

‘To know for certain that is not true, you must have some knowledge of what is being done at Akelberg.’

‘Not necessarily,’ he said, but all his tension had returned, and she knew she was on to something.

‘I remember seeing a Nazi poster,’ she went on. It was this memory that had triggered her dreadful thought. ‘There was a picture of a male nurse and a mentally handicapped man. The text said something like: ‘Sixty thousand Reichsmarks is what this person suffering from hereditary defects costs the people’s community during his lifetime. Comrade, that is your money too!’ It was an advertisement for a magazine, I think.’

‘I have seen some of that propaganda,’ Gottfried said disdainfully, as if it were nothing to do with him.

Carla stood up. ‘You’re a Catholic, Herr von Kessel, and you brought up Heinrich in the Catholic faith.’

Gottfried made a scornful noise. ‘Heinrich says he’s an atheist now.’

‘But you’re not. And you believe that human life is sacred.’

‘Yes.’

‘You say that the doctors at Akelberg are not testing dangerous new therapies on handicapped people, and I believe you.’

‘Thank you.’

‘But are they doing something else? Something worse?’

‘No, no.’

‘Are they deliberately killing the handicapped?’

Gottfried shook his head silently.

Carla moved closer to Gottfried and lowered her voice, as if they were the only two people in the room. ‘As a Catholic who believes that human life is sacred, will you put your hand on your heart and tell me that mentally ill children are not being murdered at Akelberg?’

Gottfried smiled, made a reassuring gesture, and opened his mouth to speak, but no words came out.

Carla knelt on the rug in front of him. ‘Would you do that, please? Right now? Here in your house with you are four young Germans, your son and his three friends. Just tell us the truth. Look me in the eye and say that our government does not kill handicapped children.’

The silence in the room was total. Gottfried seemed about to speak, but changed his mind. He squeezed his eyes shut, twisted his mouth into a grimace, and bowed his head. The four young people watched his facial contortions in amazement.

At last he opened his eyes. He looked at them one by one, ending with his gaze on his son.

Then he stood up and walked out of the room.