‘But she wasn’t British at all. She was half Bulgarian, and half Irish. According to the files from Sofia, her mother was a nurse from County Galway who met a Bulgarian soldier.’

‘I know.’

He couldn’t quite interpret the look that Fry gave him. Maybe she just wanted to change the subject, or maybe she really was concerned for his welfare.

‘Are you all right now, Ben? You’re not still bothered by John Lowther’s death?’

Cooper was about to say no, he wasn’t. But then he realized there were thoughts just below the surface that he hadn’t had a chance to tell anybody about until now.

‘He’d already stopped taking his medication, hadn’t he?’ he said.

‘Yes, some weeks ago. Lindsay became completely absorbed with the baby. She forgot about her brother’s needs, or maybe she thought he was well enough to cope on his own. But he wasn’t – he began to slip.’

‘I bet he knew there was something wrong. But once his thoughts became too disordered, he wouldn’t know why, or what the problem was. Unless the voices gave him an explanation.’

‘You’re empathizing with a psychotic?’ said Fry in amazement. ‘Now I’ve heard everything.’

Cooper took no notice. ‘John Lowther’s problem was that he saw too clearly, wasn’t it?’

‘What? What did he see?’

‘The ghastly, naked spectre of insanity,’ said Cooper, hardly knowing whether he was speaking out loud.

‘Where on earth does that come from, Ben?’

‘I can’t remember. It’s just a phrase that stuck in my mind from somewhere.’

Fry sniffed. ‘More likely he couldn’t live with the knowledge that his father had involved him in a murder.’

‘Yes, that as well. If he really understood what was happening.’

Cooper paused, considering his own comment. Because that wasn’t what had been haunting John Lowther in those final moments, was it? His last words, as the air had snatched him from the tower on the Heights of Abraham, hadn’t referred to Rose Shepherd, but to his sister and her children. I heard them scream. I’ll always hear them scream. So those screams must have been inside John Lowther’s head. Just one final illusion.

And Cooper knew there was something else he shouldn’t mention to Fry. He couldn’t help feeling sorry for both the Mullens and the Lowthers. The Mullens’s desperation for a girl had brought terrible consequences for them. In a way, Brian and Lindsay had sacrificed two children for one, as if they’d been playing some ghastly game of chess. A game that they’d lost, in the end.

‘The Mullens did it all for the sake of that third child,’ he said, because that was a safe way to say it.

Fry nodded. ‘And the child wasn’t even theirs.’