I locked the door of the room when he’d left. If there was any truth in his theory it was too much to contemplate; it would be the universe inverted, and I resisted opening the door on that possibility because it would be overwhelming. If this was some sophisticated attempt at framing her then I felt sick at the efficiency, and deeply wary of my involvement. It would explain the suspicion on me and Tom Marsh, on anyone she was close to or came into contact with. It might explain the closing down of Building D’s operation, and her running to Kazakhstan.

I looked again at the stills.

Images are powerful because they suggest you don’t have to think. Here’s truth. But there’s always a story behind them. In the story behind the disappearance of Joanna Lake there was an email to me. Catalyst.

One woman getting into a car. I enlarged it on the screen as if an answer would appear. It was her; no force, everything to suggest she knew what she was doing and wanted to make it discreet.

You recruit someone to the intelligence services because of their confidence and cunning, and then train them to lie for their country. They elect to transfer these skills to a private company working for the energy industry. You ask: could they ever lose their moral bearings? Go rogue?

But not for Vishinsky. Not in a million years. Surely.

In my experience, you’re working for whoever keeps you alive. I found Sergei Cherenkov’s card, wondered what he knew about all this. I was still holding it when I noticed the music videos had been replaced by grainy footage. People stampeded through a shopping mall. Behind them walked a calm, young-looking man, strolling with an automatic rifle.

People dived into shops, pulling doors closed. The man strolled past abandoned benches, fountains, potted palm trees. It cut to a news presenter reading an autocue: Sunlight shopping mall, St Petersburg.

I clicked through channels. Most were showing the same footage. Initial reports said eight people had died, twenty wounded. The attacker had been shot by police. He was Kazakh.

I left the sauna, returned to my hotel and went online. A video by a group called the Islamic Movement of Kazakhstan had gone up, claiming responsibility. It showed five Kazakh-looking men in combat fatigues with Korans and AK-47s. The landscape was semi-arid, a low chain of dusty green mountains in the background. Could have been Iraq, could have been Syria. Could have been southern Spain. It was turning up everywhere, along with their statement: We demand that Russia ceases all activities in the Middle East and Central Asia. Until Russian troops and their proxies withdraw from all Muslim lands we will wage war against you wherever we find you. You come to our land, we will come to yours.