My brain froze. If you mention Spooky Joe’s coded note, you could end up incriminating Mags instead of Mutti.

Flustered, I said, ‘She’s just not like that. She might be German, but that doesn’t mean she supports Hitler and all the terrible things he’s doing. And she has nothing to do with any of the information that passes through the lighthouse about shipping or anything. If she were to look in Pa’s logbook, I honestly don’t think she would know what any of his notes or records meant.’

A little voice hissed in my head, But Mags would – wouldn’t she? I swallowed hard, as if I could somehow get rid of the thought that way.

Pinstripe nodded. ‘I see,’ he said. He cleared his throat – that dry fox-cough. ‘Well, thank you for that information.’

‘Aren’t you going to write it down? Doesn’t it count as evidence – a character reference or something?’

Obligingly, he took a notebook out of a pocket and scribbled something down.

‘She hasn’t done anything wrong,’ I said, determined to make him listen. ‘And it’s not fair that she should be locked up just because of the country she was born in.’

He didn’t say anything.

I pressed on. ‘She’s a good person.’ I was starting to get angry. The detective didn’t seem to be listening to me at all; he was gazing out to sea again.

The rain became quieter, hardly falling now – just a damp thickness in the air. Pinstripe took down his umbrella, shook it and rolled it up. Then he looked at me. ‘I’m sorry to say this, Petra, but sometimes, good people do bad things.’

I felt a stabbing pain in my chest. Is he saying Mutti is guilty? That she is a traitor?

‘Why?’ I said, fighting back the tears that burnt in my eyes. ‘Why would a good person do bad things?’

He shrugged. ‘The world is a complicated place and war is a terrible thing. Sometimes a good person has a logical reason for doing something that is morally wrong; sometimes they feel they have no choice.’ He took a clean white handkerchief from his pinstriped pocket and offered it to me to wipe the tears away. ‘I’m so sorry, but I’m afraid this is something you are going to need to come to terms with, Petra. Very soon.’

He knew something. He knew something that must prove Mutti’s guilt, and he wasn’t telling me.

All I wanted to do then – the only thing I wanted to do – was to run straight home into the arms of my Mutti.

But she wasn’t there.