‘It took me two semesters to fully infiltrate the group, by which time I’d found out about everything they were up to. There was a lot of talk about how to support Hitler; they’d convinced themselves the population of Denmark was waiting to rise in support of him. But then they came up with a plan to burn down the synagogue in Aarhus on Passover, when the building would be full of people. They gathered all the materials they needed and drew up diagrams. At that point I tipped off the local police and a dozen of them were arrested. I even have photographs of the group somewhere. I keep my old photo albums in the hall cupboard; there’s more storage space in my father’s flat than in mine. Let me get them.’

They looked through the albums together. Some of the photos showed Hanne when she first joined the police, on patrol in Copenhagen, behind a desk, with a horse. A couple of pages she turned over very fast; those seemed to show her with a man of her own age. Then came the photographs of her as a student in Aarhus, posing outside a university building, standing windswept in a courtyard.

‘We used to go on hikes into the countryside. This was their idea of providing cover: we were a nationalist hiking group, would you believe. They also felt it was important to connect with nature. Here, this is the whole group. See if you can spot me.’

‘Not difficult. I could spot you anywhere. The Nazis aren’t nearly as good-looking as you!’

They were sitting on the floor, their backs resting against the sofa, the albums stacked in front of them. She patted his knee, as if in thanks. But Prince didn’t notice. He was staring at the photo, oblivious to everything else, a chill running down his spine.

‘What is it? You look like you’ve seen a ghost!’

He said nothing, turning over the page to look at more photos of the group. One in particular was very clear, taken in good light, the faces more in focus.

‘Who is that?’ His voice sounded uneasy.

‘That’s Greta. Greta Poulsen. She was one of the most active Nazis. In fact, she was the one who originally came up with the idea to burn down the synagogue. She served four or five years in prison. Why do you ask?’

He didn’t reply, instead picking up the album and taking it to the table to study it more closely. There was no question it was her: the hair, the eyes, the lips… all the same. ‘You know you asked me to think of someone who might have betrayed me?’

Hanne nodded.

‘Well, I’ve found them.’

Chapter 8

Copenhagen, November 1942

They argued long into the night, at one stage having to stop themselves when they realised they’d actually been shouting.