Cooper groaned. And then he lay listening to the swish of someone passing back through the grass towards the trees, gradually moving further away from him, further away with his only means of summoning help.

After all the photographs had been taken, Diane Fry bent over Robertson’s body and went through his pockets. She took out his wallet, an address book, an opened letter, car keys and a mobile phone. Finally, she pulled out a blue plastic card with lettering superimposed over a red heart. She showed it to DI Hitchens, who had just ducked under the tape of the inner cordon.

‘An organ-donor card. Why did he have this on him, I wonder?’

‘You’re supposed to carry those things with you,’ said Hitchens. ‘Otherwise, they’re not much use. Who does he give as his next of kin? His daughter?’

Fry turned the card over. ‘Well, well. It says: “In the event of my death, contact Mr Vernon Slack.” Full name and signature. And it says he wanted his organs to be used for the treatment of others.’

Hitchens studied the body. ‘It’s a bit late for that. He’s beyond being any use to anybody.’

‘But surely he wasn’t related to Vernon Slack?’

‘You don’t have to give the name of a family member. It can be a friend, or a colleague.’

‘Just a friend. OK.’

‘Bag the card with the rest of the stuff, though. There might have been more to the relationship between them than we think.’

Fry nodded. As she slid the organ-donor card into an evidence bag, she read the slogan in white lettering across a bright red heart: I want to help others to live in the event of my death. Well, you couldn’t really wish for more than that from your death. No matter what you’d done during your life.

Cooper looked up and saw Vernon Slack standing over him with a rifle. Staring at the end of the barrel, he thought of the bullet wound in Tam Jarvis’s dog, Graceless. Tears were running down Vernon’s face.

‘Who have you killed, Vernon?’ said Cooper.

Something moved and glittered in Vernon’s eyes. Then it was gone again instantly. It was as if two black beads had rolled over, revealing their glistening cores for a second.

‘It doesn’t matter now,’ he said. ‘I might have killed someone, I might not. It’s all the same in the end.’

Cooper thought of Abraham Slack. The old man had moved to Greenshaw Lodge so that Vernon could take care of him. But the phrase ‘take care of’ was open to a different meaning. The house hadn’t seemed a welcoming place, not the sort of home you’d expect to rest in and be looked after. Instead, it had felt sparse and cold, more like a house that someone was preparing to leave.

He tried to sit up, forgetting the rifle, or the fact that it might be more sensible to keep still.

‘Where’s your grandfather?’ he said.

But Vernon only stared at him ‘You aren’t very clever. You’re not clever enough, and you’re too slow. If you’re stupid, you’ll get beaten.’