‘I’m not saying they wouldn’t want to. They want secure borders. Russia’s idea of a secure border is one with Russians on both sides. But there are limits. Think of the potential consequences.’

‘Nations aren’t rational actors,’ she said. ‘They’re bitter old men.’

‘But you think you can predict what they’re going to do.’

‘You don’t need to be rational to be predictable.’

Sometimes it seemed as if the entire intelligence service had become obsessed, chasing an infinite meteorology. It had started out simply enough, with a search for algorithms that could warn us of attacks, identifying digital landscapes that had previously led up to terrorist incidents: communications activity, social media, financial transactions, geographical movement. Then it turned to visual patterns: how someone moves around a city, their posture, their silhouette, whether they have a bag, how the bag is carried. All the messages you write without intending to.

This is mankind’s eternal quest, I’d argued. To protect ourselves from randomness. To know everything. The machines allowed fixation. In the old paper archives you could see the sickness of an obsession, the visible mess of paper, stacks and annotations. One click of a mouse could deliver three hundred lifetimes of obsession.

At five past midnight my phone buzzed. Reza had sent through a message.

This her?

I opened the attached file. It was a photo of a group: four men, three women, wrapped up for a hike. They were outside, in the snow, a boxy concrete building behind them. One of the women’s faces had been circled. She was standing at the back of the group. Almost as if she hadn’t wanted to be picked up.

It was her.

She wore a woollen hat and hiking boots. Some of the other members of the party had walking poles. Was this Joanna as Vanessa? I didn’t recognise any of the other individuals. There was no geographic tag to the image. I was left with the blurred face, some trees that looked like pines breaking the deep snow, the building behind her. A faded sign said Kinoteatr. It was a derelict cinema: ‘Miners’ Cinema’, according to signage grown encrusted in icicles.

Reza’s analysts had retrieved it from a computer in Berlin they were monitoring, which had received it on Facebook in a posting originating in Kazakhstan. Eco-activists. It had been posted a couple of months ago. The activists connected to various campaigns against pollution, but had been careful to remove geotags and any reference to a location. It wasn’t Astana. Behind the cinema, a wall of coniferous trees clung to a steep white hillside.