I glanced at the German policeman whom Vigée had brought along, so that if I did identify de Boudel, he might be arrested immediately and then extradited to France.

“Forget it,” I growled. “I just never had to blow the whistle on anyone before, that’s all. I guess there’s something about it I don’t like. Who knows?” I started on a new stick of gum. “If I see this fellow, what do you want me to do, anyway? Kiss him on the cheek?”

“Just point him out to us,” Vigée said patiently. “The police inspector will do the rest.”

“Why so squeamish, Gunther?” asked Grottsch. “I thought you used to be a policeman.”

“I was a cop, it’s true,” I said. “Several thousand midnights ago. But it was one thing arresting some old lag. It’s something else when it’s an old comrade.”

“A nice distinction,” said the Frenchman. “But hardly correct. It’s not much of an old comrade who sells his soul to the other side.”

There was a loud cheer along the platform as, in the distance, we heard the whistle of an approaching steam locomotive.

Vigée made a fist and pumped his biceps excitedly.

“Who gave you this tip, anyway?” I asked. “That de Boudel would be on this train?”

“The English Secret Service.”

“And how did they find out?”

The train was now in sight, a shiny black locomotive wreathed in gray smoke and white steam, as if a kitchen door in hell had been flung open. It was hauling not cattle wagons, as would have been more typical of a Russian POW train, but passenger carriages; and it was immediately plain to me that upon entering Germany, the prisoners had been transferred onto a German train. Men were already leaning out of open windows, waving to the people running alongside the track or catching bunches of flowers thrown up into their arms.