Rathbone’s smile vanished, a look of pain in his eyes. Monk saw it and understood. Monk was glad it was not his skill or judgment on which rested the weight of the saving or losing of a man’s life.

“I’m sorry,” Monk apologized. It was probably inappropriate, but for a moment they were not adversaries. They felt the same pity, and revulsion, at the thought of hanging. “I have no wish to prosecute him at all,” he went on. “When I first found Parfitt’s body, I considered not even looking for whoever killed him, after I’d seen the boat and the boys kept there. But when the cravat turned up, I had no choice.”

Rathbone’s face was bleak. “I know that. What is it you want, Monk?”

“The man behind it. Don’t you?”

“Of course. But I have no idea who that is.” He met Monk’s eyes directly, without a flicker. Was he remembering the night when Sullivan had killed Phillips so hideously, and then himself, after he had said that the man behind it all was Arthur Ballinger? Why had he pointed to Ballinger? Had it been anger, ignorance, madness, while the balance of his mind turned? Had it been revenge for something quite different? Or the truth?

Rathbone could not afford to think that the man was Margaret’s father. The price of that would be devastating, yet nor could he afford to ignore it. Monk did not want to do this either, but he also could not look away, for Cardew, and, more important to him, for Scuff.

“No …” Monk said slowly. “But if the right pressure were put upon Cardew, then he might give enough information for us to find out.”

“Why should he?” Rathbone asked, his voice tight and careful. “Surely by doing that he would automatically be admitting to the most powerful motive for killing Parfitt. I know that you believe you can prove that he did kill Parfitt, but he swears he did not.”

“And you believe him?” Monk said. “Actually, there is no point in your assuming that, even if you are right. It is what the jury believes that matters. If he will give us a record of every payment he made to Parfitt, dates and amounts, we might be able to trace it through Parfitt’s books. If it comes out in the open in court, it could shake other things loose.”

“And hang Cardew for certain,” Rathbone said quietly. “His own society will never forgive him for frequenting a boat like that, whether he killed the bastard who ran it or not.” His mouth pulled into a delicately bitter smile. “Apart from anything else, it would betray the fact that men of his social and financial class were the chief clients, and enablers of creatures like Parfitt. And while that is true, making it public is another thing altogether.”