‘Monsieur Schreiber, there are some photographs I’d like to see. Anything from the summer of 1989.’

‘The year your parents and your brother died in that accident?’

Jakob spoke with a strong German accent. He talked loudly to drown out the radio, a German station that didn’t broadcast music, just the monotonous voice of a presenter.

‘I understand, I understand.’

While they were still talking, he hurriedly took out his mobile phone and started tapping on the keys. He did this for more than thirty seconds, and Clotilde thought about returning his rudeness and getting up to look for the pictures she wanted to see.

‘Sorry, Mademoiselle Idrissi,’ Jakob said just as she was about to do so. ‘I’m only an old man with a little boy’s hobbies. Do you know the programme Who Wants to Win a Million in Their Own Sitting Room?’

Clotilde shook her head.

‘It’s the same as on television, but adapted to the radio. You have to subscribe with your phone and download an app. When the presenter asks questions, you have to reply in less than three seconds, so there’s not enough time for you to look up the answer on the internet. You tap A, B, C or D. If you’ve got it right, you progress. It’s only the last three questions that aren’t multiple choice.’

‘And you really win a million if you get all the questions right?’

‘Yes, apparently. It’s all paid for by advertising. The programme is a huge hit in Germany, there are hundreds of thousands of subscribers. But like the vast majority of Germans, I’ve never got beyond the tenth question.’

‘And now?’

‘I’m on the ninth, you reach the second level on the twelfth. But I’ve got time, the next question won’t come up for another fifteen minutes. It’s all the advertising, as I said. So, the summer of ’89, is that the one?’

Jakob got to his feet. The seventy-year-old still seemed quite alert. He went into another room of his mobile home.

‘Hermann’s room,’ he explained. ‘I turned it into a dark room in the late nineties.’

Dozens of filing boxes, all labelled and numbered, were lined up neatly on the shelves.

Summer ’61.

Summer ’62.

And so on up to 2015. The most recent years were archived in several files.

‘I take a few hundred photographs a year,’ Jakob explained. ‘Particularly since it all went digital. But even before that, I used up dozens of films each summer. So here we go, ’89.’

He climbed on to a stool, took down the box and came back to Clotilde.

‘If your parents didn’t die in an accident, but were murdered, there is every chance that the murderer’s face will appear in one of these shots.’

She thought at first that he was serious, but then the old German smiled at her.