Aaron fished it out. Wildsmith looked at the paper in silence for what felt a painfully long time, and put it down. “I stand by it. There’s the sense that he’s superior, or untouchable, or above the normal run of humanity, and it goes with an absolute callousness. Sadistic, even. I’d be really astonished if he hasn’t killed.”

“We have had quite a large war,” Aaron observed, a last throw of the dice.

“No, it’s not that. Or at least, not just shooting at the other side. If it was in the war, it was killing unarmed prisoners, or civilians. He does things that are not allowed because it gives him pleasure, and because—well, why shouldn’t he?”

“Hell.”

“Is there any chance you could tell me what’s going on? I mean, do you know who he is?”

“Yes.”

“And you’re not happy that I passed your test, because that suggests I’m right about him, and you don’t like that at all.”

“No.”

Wildsmith hesitated. Then he leaned forward, and put his hand very gently on Aaron’s knee.

“Look,” he said. “I have no idea about this, but I do know that you’re a decent man. More than decent. I am absolutely sure you’ll do the right thing if you can.”

Aaron tried to ignore the warm touch of his hand. He ought to shift his knee, shake it off. He didn’t. “I don’t know what I can do. If I have the nerve to do it. I’m— Christ. The truth is, I’m afraid.”

“This is sounding worse by the minute,” Wildsmith said. “Do I want to know?”

“I didn’t want to know,” Aaron said, and the words rasped in his throat. “I’m sorry. You ought not be involved. I should go.”

“No, stop. Have you involved me? I mean, does anyone other than you know about this experiment, or my conclusions?”

“Hollis. He was on the embezzlement case, but he doesn’t know who the ringers were.”

“The...?”

“There were five suspects. We felt one in five was too good odds for guessing so I got three other people to give me their writing. I didn’t mention you.”

“And number seven was one of those ‘ringers’, because if he was one of the suspects in Hollis’s case, it wouldn’t be your problem. And...I’m going to speculate you asked people at work... Oh fuck. Number seven’s a copper? CID?”

Aaron really should not have come here. Wildsmith was too good a guesser. “This is not something to repeat.”

“On the contrary,” Wildsmith said. “It’s bloody well something for you to repeat. It’s not something I’m going to repeat because I’ve had quite enough trouble from the Met, thank you. Hollis isn’t going to tell anyone about this, is he?”

“He doesn’t know who the ringers were.”