Then he said, ‘You reckon that whoever had a knife to your throat is not the same person who stuck a camera in your face.’

‘He can’t be, can he?’ I said. ‘Whoever put me down wouldn’t have followed me across a ploughed field and through some woods just to shoot this funny little film, would he?’

‘How far did you crawl?’

‘I was running through those woods for perhaps five minutes. It would have taken a lot longer to crawl back. But that film wasn’t taken anywhere near where I was attacked. It wasn’t taken at the pigpen at the farm. It wasn’t taken in the ploughed field. It was filmed when I was back at Potter’s Field. It was filmed on the edge of the playing fields.’

‘So who put it on the internet? Where did Bob get it from?’

‘I don’t know. It doesn’t matter. That school has a thousand boys and they all have phones with cameras. There are reporters crawling all over the place. The staff. Everybody’s walking around with a camera crew in their back pocket. What it proves – what I think it proves – is that Bob the Butcher is full of bullshit. Whoever took that film didn’t kill anyone. And neither did he.’

I closed my laptop and we looked at each other. Sergeant Caine folded his heavy arms. Then he nodded once.

‘Yes,’ he said, ‘I think you’re probably right.’

‘Thank you.’

‘You’re welcome. What’s the problem?’

‘The problem is they’re chucking everything they’ve got at Bob,’ I said. ‘All of our resources are being poured into looking for Bob the Butcher, serial killer of the year. Operation Fat Boy is being led up a dead end.’

A spasm of pain travelled up my spine and I ground my teeth together, arching my back until it passed.

‘You want to find whoever messed up your back,’ Sergeant Caine said.

‘I want to find the killer.’ I took a breath and let it go. ‘And you can help me.’

‘How can I do that?’

‘I want to see the From Hell letter,’ I said.

He looked away, then looked back at me. Suddenly he was angry.

‘The From Hell letter? Do you know what you’re asking? The From Hell letter was lost.’

‘I don’t think so,’ I said. ‘I think it’s here. I think it’s somewhere in this room. I think it’s in your possession.’

‘What do you know about the From Hell letter, detective?’

‘I know that it was also known as the Lusk letter,’ I replied. ‘It was a letter posted in 1888 by a person unknown who claimed to be Jack the Ripper. What made the police think it was the one genuine correspondence from Jack the Ripper was that it arrived with part of an internal organ from a human body.’