‘The one about the woman who lived in a cottage near your farm when you were a child.’

‘Old Annie?’ said Cooper. ‘Well, I can’t see the similarity myself.’

‘You said she didn’t speak to anyone for weeks on end, then talked far too much when she was in company. As if she had to prove that she could still hold a conversation.’

Cooper looked surprised. ‘Yes, I did say that.’

‘Also, you mentioned finding her frightening. A slightly hysterical tone to her voice, you said. That’s what John Lowther reminded me of.’

‘I know what you mean.’

‘Well, there’s a job for you to do, Ben. I’ll call ahead and get the interview cleared with the hospital.’

‘Hospital?’

Fry explained to him. As Cooper prepared to leave, she listened to the silence of the apartment, well insulated and far enough away from the main road to deaden the sounds of traffic.

‘We’ve got to find John Lowther,’ she said. ‘He could be a lot more dangerous than Brian Mullen.’

Fry dialled the number of the bungalow in Darley Dale, where she had been only half an hour before.

‘Mrs Lowther, where would your son go? What place might he be heading for right now?’

She could picture the Lowthers looking at each other, deciding what answer to give. Fry half expected the phone to be handed to the husband, but it was Moira who spoke.

‘When John wants to be alone, he likes to go up to the Heights of Abraham.’

An hour later, Dr Alexander Sinclair took off his white coat and put on a suit jacket, transforming himself from a clinical psychologist into a business executive. He sat down at his desk, opened a file and put on his glasses.

‘You appreciate this is very exceptional, Detective Constable.’

‘The circumstances are exceptional, too,’ said Cooper. ‘We wouldn’t have asked you for this information otherwise.’

‘Yes, so I’ve been persuaded by your senior officers. I’m only agreeing to this conversation on the understanding that I’m acting in the interests of my patient, and no further.’

Sinclair peered over the top of his glasses, a mannerism that Cooper hated. It made him look like a disapproving schoolteacher.

‘We’re extremely concerned for Mr Lowther’s safety,’ he said. ‘Not to mention the safety of others that he might come into contact with.’

‘Very well. There are some specific details of this patient’s history that I can’t go into, but I can answer general questions about his condition, which might help you.’

‘Well, we already know that John Lowther spent three months in a psychiatric unit in Leeds.’

‘That’s correct.’

‘Was he sectioned?’

‘No, he admitted himself voluntarily, following a series of psychotic episodes.’

‘What sort of episodes?’

‘Mr Lowther was experiencing auditory and visual hallucinations.’

‘Auditory –?’

‘He heard voices,’ said Sinclair impatiently. ‘And “visual” means he was seeing things.’

‘Thank you.’