All along I had assumed that Harriet Throsby’s murder was in some way connected to Mindgame. After all, the knife that had killed her had been stolen from the Vaudeville and there seemed to be no escaping the fact that someone had deliberately tried to frame me. That was still the biggest puzzle, as far as I was concerned. It was easy enough to understand why the killer hated Harriet Throsby. But what on earth could I have done to make them want to harm me? So far, Hawthorne had said very little about this aspect of his investigation. He might have blocked the DNA analysis of my hair, but he hadn’t offered any theory as to how it might have got onto the body in the first place. The same was true of the dagger with my fingerprints, the CCTV images, the Japanese cherry blossom. Perhaps it was because he still suspected me more than anyone else of having committed the crime.

But what he had said outside the accountant’s office was true. It was extremely unlikely that Harriet had been killed because she’d written a bad review. The events at Moxham Heath provided a much more likely explanation. A man had died. Two boys had gone to prison. A family had been destroyed. And Harriet had written about it all. Badly. Maybe someone had decided it was time she paid the price.

We took a taxi from Chippenham station, moving from ring road to motorway to country lane. The driver had been glum at first, reluctant to come out so far, but he’d cheered up when Hawthorne told him that we’d be using him all day. I swear I’ve spent more on taxi fares than I’ve earned from the books I’ve written about Hawthorne, but for once I didn’t complain. We’d just missed the eleven o’clock train from Paddington and we’d had to wait thirty minutes for the next one. This was the slow service, stopping at Reading, Slough, Swindon and another half-dozen stations I’d never heard of. As much as I’d tried to concentrate on the book, I hadn’t been able to keep Cara Grunshaw out of my thoughts. I half expected to see her waiting on the next platform. I felt like a fugitive in a Hitchcock film.

We were travelling down a country lane, through a tunnel of beech trees sporting their new spring leaves and between verges scattered with wild flowers. The light had turned green and there were motes of dust dancing in the sunlight. Ahead of us, a drystone wall twisted into the distance as if beckoning us to follow. I’m always dazzled by the beauty of the English countryside at the start of spring, but Wiltshire has a particular trick of throwing you back in time. At that moment, there was nothing to suggest we were still in the twenty-first century, apart from the car we were sitting in.

‘Hold it!’ Hawthorne broke into my reverie, calling out to the driver. ‘Turn right here.’