The caption pointed out that a sick or injured horse was supposed to be killed straight away, and suggested that the animal had been left to lie in the yard because it had arrived at the slaughterhouse outside normal operating hours when the butchering line wasn’t running. Legislation said that for meat to be deemed fit for human consumption, an animal must be bled immediately after being shot or stunned. Therefore, it had to wait to be killed until the butchering line was ready. Yet the law also said that a seriously injured animal should be despatched without delay.

‘Even if that’s true,’ said Hitchens, when Cooper pointed it out, ‘it’s a matter for the licensing authorities. The RSPCA, maybe. Not us.’

‘It’s relevant to us if it suggests a motive,’ said Cooper.

‘The man in the film . . . ?’

‘Yes. The one in the yard with the injured horse. I’m pretty sure that was Patrick Rawson himself.’

MINUTES AFTER HER return from Sutton Coldfield, Fry found herself sitting in the DI’s office, warily eyeing a stack of papers he was extracting from a file. If Hitchens wanted to share something with her, it probably wasn’t good news.

‘No live investigations or outstanding offences for Patrick Rawson?’ he said vaguely.

‘None, sir. But that doesn’t rule out the involvement of angry customers from earlier offences. Someone whose name might be on Dermot Walsh’s list.’

‘Good point. We’ll have to speak to them all.’

‘Given time, that might be possible. At the moment, I’m more concerned by the fact that I can’t contact the partner, Michael Clay. Without him, we can’t even start to analyse Mr Rawson’s business affairs properly.’

‘Yes, I heard. But he’ll turn up, won’t he?’

‘I hope so.’

Hitchens frowned and looked up. ‘Diane, have you ever heard of a disease called trichinosis?’

‘What? No, I haven’t. But it doesn’t sound like something I’d want to be diagnosed with.’

‘You’re exactly right. Trichinosis is a parasitic disease caused by a nematode worm, whatever that is. I don’t like the sound of it, personally. Trichinella spiralis.’

‘Symptoms?’

‘Initially, swelling of the eyes, diarrhoea, vomiting, and abdominal pain. Also fatigue, fever, headaches, shivering, coughing, aching joints, muscle pains. In severe infections, there may be heart and breathing problems, or difficulty co-ordinating movements. In extreme cases, death can occur.’ Hitchens laughed drily. ‘I like that – “death can occur”. That should be our motto.’

‘You don’t look as though you have any of those,’ said Fry. ‘But I suppose it’s difficult for me to tell unless you stand up and walk about a bit.’

Hitchens didn’t seem to be listening as he ran his eye over a sheet filled with dense paragraphs of text.

‘Trichinosis is actually quite rare in this country,’ he said. ‘Or it used to be.’

Fry felt a small shiver of unease. She wasn’t a hypochondriac by any means, but even so, she didn’t like the idea of this disease. What was that about a nematode worm? Just the name of it sounded disgusting.