There were three little parks where I could take the dog. The one closest to my flat – St John’s Gardens – had originally been a cemetery but the dead bodies had all been removed (to Woking, which must have surprised them) and what remained was an irregular space penned in by iron railings with a patch of scrubby grass, flower beds, paths and benches. The local council had taken to locking it at night to keep the drug dealers out, but occasionally they forgot – and fortunately that was the case tonight. I slipped inside and let the dog off the lead, then stood there watching him sniff around. The ground was wet underfoot, but I could feel a hint of spring warmth in the air, carrying with it the distinct scent of marijuana. There were empty offices on three sides of me, the back of a terrace of houses on the fourth. The dog ignored me. I felt very alone.

I don’t know what spooked me first. It was the sound of footsteps, I think, coming up the narrow alley that led from Turnmill Street. There was nothing unusual about that. Other dog walkers used the park at night: I didn’t know their names, although I knew their dogs’. However, these footsteps sounded too heavy, too slow and deliberate. Work on Crossrail was continuing day and night at Farringdon Station, which was out of sight around the corner, and they must have left a single floodlight on. A shadow stretched up the road towards me. It led to a single figure that suddenly stopped, silhouetted against the light, very much like Max von Sydow in the poster of the 1973 film The Exorcist. It was a man, standing there, silent and unmoving. And there could be no mistaking it. He was looking at me in a way that made me feel vulnerable, exposed.

‘Lucky!’ I called out. This wasn’t an observation. It was the name of my dog.

The dog refused to come.

Despite everything that had happened, it had never once occurred to me that I might be in danger, that the smiling face of somebody I might have met even today could have been concealing the mind of a psychopathic killer and that they might have further designs on me. After all, one of them had walked round to a house in Little Venice and stabbed Harriet Throsby to death in her own hallway. That same person had tried to frame me. Suppose they now felt threatened? Suppose Hawthorne had said something during one of the interviews that had told them the game was up? They might not have any reason to kill me – but mad people don’t need a reason. If they’d killed Harriet because of something she wrote, might they not do the same to me? In my case it would be Mindgame. She hated it. I created it. Maybe we both needed to be punished.

All these thoughts swirled in a sort of vortex through my mind. I tried to persuade myself that I was being ridiculous, that I was just a few minutes from my home and perfectly safe. But suddenly I had no desire to be out here on my own. I called the dog again and this time he must have recognised the anxiety in my voice because he padded over and allowed me to attach the lead. The man still wasn’t moving. He looked enormous, slanting out of the pavement like some sort of golem.