‘Look again.’ She handed him the letter. ‘Appendicitis.’

‘What is the significance?’

‘Kurt had had his appendix removed.’

‘I remember,’ her father said. ‘He had an emergency operation, just after his sixth birthday.’

Carla’s sorrow was mixed with angry suspicion. Had Kurt been killed by a dangerous experiment which the hospital was now trying to cover up? ‘Why would they lie?’ she said.

Erik banged his fist on the table. ‘Why do you say it is a lie?’ he cried. ‘Why do you always accuse the establishment? This is obviously a mistake! Some typist has made a copying error!’

Carla was not so sure. ‘A typist working in a hospital is likely to know what an appendix is.’

Erik said furiously: ‘You will seize upon even this personal tragedy as a way of attacking those in authority!’

‘Be quiet, you two,’ said their father.

They looked at him. There was a new tone in his voice. ‘Erik may be right,’ he said. ‘If so, the hospital will be perfectly happy to answer questions and give further details of how Kurt and Axel died.’

‘Of course they will,’ said Erik.

Walter went on: ‘And if Carla is right, they will try to discourage inquiries, withhold information and intimidate the parents of the dead children by suggesting that their questions are somehow illegitimate.’

Erik looked less comfortable about that.

Half an hour ago Walter had been a shrunken man. Now somehow he seemed to fill his suit again. ‘We will find out as soon as we start asking questions.’

Carla said: ‘I’m going to see Frieda.’

Her mother said: ‘Don’t you have to go to work?’

‘I’m on the late shift.’

Carla phoned Frieda, told her that Kurt was dead too, and said she was coming to talk about it. She put on her coat, hat and gloves then wheeled her bicycle outside. She was a fast rider and it took her only a quarter of an hour to get to the Francks’ villa in Schöneberg.

The butler let her in and told her the family were still in the dining room. As soon as she walked in, Frieda’s father, Ludwig Franck, bellowed at her: ‘What did they tell you at the Wannsee Children’s Home?’

Carla did not much like Ludwig. He was a right-wing bully and he had supported the Nazis in the early days. Perhaps he had changed his views: many businessmen had, by now, though they showed little sign of the humility that ought to go with having been so wrong.

She did not answer immediately. She sat down at the table and looked at the family: Ludwig, Monika, Werner and Frieda, and the butler hovering in the background. She collected her thoughts.

‘Come on, girl, answer me!’ Ludwig demanded. He had in his hand a letter that looked very like Ada’s, and he was waving it angrily.

Monika put a restraining hand on her husband’s arm. ‘Take it easy, Ludi.’

‘I want to know!’ he said.

Carla looked at his pink face and little black moustache. He was in an agony of grief, she saw. In other circumstances she would have refused to speak to someone so rude. But he had an excuse for his bad manners, and she decided to overlook them. ‘The Director, Professor Willrich, told us there was a new treatment for Kurt’s condition.’