“Because Otto still hasn’t found your file, Emil. And because you don’t want to give him any reason to start looking for it again. Or you might find yourself back in the Punch. His words, not mine. But I’m like a brother to that man.”

“I always thought coppers killed their brothers when they were still in their cradles.”

“Ask me in. There’s a good fellow. It’s a bit noisy out here, and you wouldn’t want me to raise my voice, now, would you?”

Emil Linthe stepped aside. At the same time he drew up his suspenders and picked up a cigarette he’d left burning in an ashtray on a ledge inside the door. As I came inside, he closed the door and then quickly moved ahead of me along the corridor to close the sitting room door. But not soon enough to prevent me from seeing what looked like a printing press. We went into the kitchen.

“I told you, Emil. I’m not here to squeeze your wrists.”

“The leopard doesn’t change its spots.”

“As a matter of fact, that’s exactly what I wanted to talk to you about. I hear you can do exactly that. For the right money. I want you to give me what Otto Trettin called an Aryan transfusion.”

I told him the problem about my grandmother.

He smiled and shook his head. “It makes me laugh,” he said. “All those people who got on the Nazi train, now running back down the aisle to look for the station they started from.”

I might have told him I wasn’t one of those people. I might have admitted I wasn’t a cop, but I didn’t want to deliver myself into his potentially blackmailing hands. Linthe was a crook after all. I needed to hold on to the whip, or else I might lose control of a horse I planned to ride for as long as I needed it.

“You Nazis are all the same.” He laughed again. “Hypocrites.”

“I’m not a Nazi. I’m a German. And a German is different from a Nazi. A German is a man who manages to overcome his worst prejudices. A Nazi is a man who turns them into laws.”

But he was too busy laughing to listen to what I was saying.

“It wasn’t my intention to amuse you, Emil.”

“Nevertheless, I am amused. It is rather amusing.”

I grabbed him by the braces and drew them tight in opposite directions so that I was half strangling him, and then shoved him hard up against the kitchen wall. Through the window, just north of Moabit, I could make out the shape of Plötzensee Prison, where recently Otto had seen the falling ax in action. It reminded me to be gentle with Emil Linthe. But not too gentle.

“Am I laughing?” I slapped him on one cheek and then the other. “Am I?”

“No,” he yelled irritably.

“Perhaps you think that file of yours really is lost, Emil. Perhaps I need to remind you what’s in it. You’re a known associate of the Hand in Hand, a very nasty little criminal ring. Also of Salomon Smolianoff, a Ukrainian counterfeiter who’s currently doing three years in the Dutch cement for forging British banknotes. You did three in the Punch for the same offense. Which is why you’ve developed a profitable little sideline forging documents. Of course, if they ever catch you forging currency again they’ll throw away the key. And they will, Emil. They will. I can guarantee it. Because if you don’t help me I’ll walk straight round to the Charlottenburg Police Praesidium and tell them about the printing press in your living room. What is it, a platen?”