‘Well, you must put your name up there along with an address and any other means of getting in touch, such as telephone numbers or regimental details. Also put the names of anyone you are looking for. Your friend Miriam, all your family.’

‘Is there anyone else here who might know her. I believe this place somehow kept working throughout the war. She might have sought work as a nurse.’

‘I have been here throughout the war. I was classified half Christian and somehow escaped the transports. If she had been here I would know her. Do you have a picture?’

He pulled the photograph from his pocket and presented it to the doctor. He instantly saw the knitting of her brows, as though the face meant something to her.

‘You’ve seen her?’

The doctor nodded but said nothing.

‘Well?’

‘I know the face, but I don’t recognise the name.’

‘Perhaps she was using a false name. I imagine many of the invisibles were.’

‘Perhaps.’ Her response was curt and unfriendly.

‘Is something the matter, Doctor? Do you know something?’

Dr Kuhn handed the photograph back to Heck. ‘Forget about her. Forget she ever existed and get on with your life, Lieutenant. And please, never show that photograph around here again.’

‘You think she’s dead? Was she discovered by the Gestapo?’

‘I don’t know. She had changed her name to Miriam Berenbaum.’ Dr Kuhn rose to her feet. ‘I’m afraid I have nothing more to tell you, Lieutenant Heck.’

‘But when did you meet her? Did she come to the hospital as a patient or did she work here? When did you last see her? Surely you must have heard or seen something?’

‘Good day, Lieutenant. I’m sure you can find your own way out.’

‘No! You cannot just leave it like that. You know something, Doctor. I would rather hear the truth than be left in limbo. Was she deported, or killed?’

‘There is nothing more to say. Now, please, I am very busy.’

‘Her father was a doctor, so it is entirely possible she came here to work. Perhaps you knew him – Herr Dr Rabinowitz?’

‘No, I never met your Dr Rabinowitz.’ She was moving towards the door to open it for him.

He couldn’t allow it and pulled out his pistol. ‘Tell me what you know.’

She stopped and gave him a look of utter disbelief and scorn. ‘You would shoot me? Then you are just like them. You are just like her.’

He was stupefied by her words. How could drawing a gun be remotely similar to Miriam? ‘What do you mean?’ he demanded.

‘You really don’t know, do you.’ She let out a long unhappy sigh and walked back to her chair behind the desk. ‘Put away your gun, Lieutenant. I will tell you everything I can about Miriam Berenbaum.’

Heck felt a chill of horror. ‘What is there to tell? I don’t understand.’