‘All right, but it seems unlikely. And Barbara Hudson –’

‘– has a doctorate in Sociology. The subject of her PhD thesis was the study of social influences on styles of moral reasoning.’

‘Really? How do you know that, Diane? Did you ask her?’

‘No, I enquired at her former university in Nottingham.’

‘A PhD?’ said Cooper. ‘So she’s actually Dr Hudson. She doesn’t use the title.’

‘Very few people do. Not in this country. They know that members of the public assume you’re a medical doctor and want to tell you about their chronic piles at every opportunity.’

‘OK. Any more?’

Cooper didn’t really have to ask. He knew perfectly well there was one more. He could see the last file clutched in Fry’s hand. Without a word, she placed it on the desk with the name face up, so that Cooper could read it for himself.

‘Well, what a surprise,’ he said. ‘Professor Freddy Robertson.’

‘You made enquiries about him yourself,’ pointed out Fry.

‘I was curious.’ Cooper turned back the pages in his notebook. ‘Look, he does a lot of work for the Rotary Club, Eden Valley Hospice, Cancer Research.’

‘So? Public charity and private iniquity?’

He looked up from his notebook. He wasn’t sure if Fry was quoting or not. But he was growing used to it from the time he’d spent with Robertson, so he didn’t bother asking.

‘Since he retired, he’s developed this interest in Thanatology.’

‘Yes, but …’

‘I’ll make the call, shall I?’ said Fry.

Cooper could tell that Freddy Robertson answered the phone almost immediately. Perhaps he spent his time waiting anxiously by the phone for someone to ask him for his advice. All he wanted was a chance to share his knowledge.

‘Oh, Sergeant …’ said Robertson when he answered his door a little while later. ‘I’m sorry, I’ve already forgotten your name.’

‘DS Fry, sir.’

The professor smiled. ‘DS Fry, yes.’

Fry stood in the hallway and looked at the coat rack, listening to Robertson’s chatter about his Edwardian gentleman’s residence without really hearing a word. It was Robertson himself she was interested in. And his voice. Particularly, she wanted to listen to his voice.

‘Thanatology,’ she said when he’d finished. ‘What does that mean exactly?’

‘It’s named after Thanatos, the personification of death. In Greek mythology, he’s the son of Nyx, the goddess of night. His Roman counterpart is Mors.’

‘Oh? Is that Inspector Mors?’

‘No. The Latin Mors, the Roman god of death, from whom we get mortality and mortuary.’

‘I was joking,’ said Fry.

Robertson inclined his head. ‘I apologize, Sergeant. I don’t always appreciate other people’s humour. You were making a reference to a well-known television programme perhaps?’

‘Yes.’

‘That sort of reference always goes over my head, I’m afraid. I’m rather out of touch with popular culture.’

He walked on ahead into the house. Fry looked at Cooper. ‘Was he apologizing just then?’

‘I think so, Diane.’

‘So why do I feel as though I’ve been insulted?’