We climbed the spiral stairs, through the service room, all the way up to the lantern room at the top. As we climbed, my mind was racing ahead, trying to remember all the things that were usually lying around up there. Could there be anything that would make them think Mutti was a spy? I led the way, so I could pause for a moment at the top of the narrow stairs, feigning breathlessness and blocking the pinstriped man’s view of the room.

I could see drawings, pencils, binoculars . . . Oh, God . . .

‘I won’t keep you long,’ Pinstripe said, and pushed gently past me into the lantern room. ‘Oh, I say – what a view!’ He stood there, awestruck for a second (as most people do when they step into our lantern room for the first time). ‘We’re up in the clouds!’

I could hear the heavy boots of the two other policemen thumping up the stairs behind me. I didn’t have time to hide anything.

‘What exactly are you looking for, sir?’ I managed to say, aware of a familiar numbness spreading up from my toes . . . I knew that feeling: I was starting to freeze.

Pinstripe didn’t reply, but the first policeman did. He almost fell upon the binoculars as he lurched into the lantern room: ‘These’ll do for a start,’ he said, examining the binoculars very suspiciously. He put them into a special bag he took from his pocket, handling them with care. Not a very pleasant-looking chap, I thought: he had an oily moustache that drooped across his top lip like a damp bootlace.

‘We’ll have to check them for fingerprints,’ he whispered to his colleague with an air of self-importance.

The numbness was spreading up my legs now, through my hips and – with a surge of nausea – through my tummy too. My fingers clung stiffly on to the handrail at the top of the stairs. Mags wasn’t here to be my fierce big sister. Pa was downstairs, in pieces. I had to be braver. Petra Zimmermann Smith, I said to myself, You are the only one who can help Mutti right now.

‘Of course they’ll have my mother’s fingerprints on them,’ I managed to say, my words catching slightly in my throat. ‘They’ll have all our fingerprints on them – they’re our binoculars!’

‘Oh, yes?’ said the second policeman, noticing me properly for the first time. ‘Your binoculars. And what exactly do you all look at through these, then?’

I rolled my eyes at the policeman’s ignorance.

‘Birds, mainly,’ I said, ‘or the moon, or boats . . .’ My throat closed up. Was looking at boats too incriminating?

He narrowed his eyes at me.

Behind the policemen was a pile of Mutti’s drawings. Would they class those as evidence? Probably. I would have to distract them.