Colonel Welsh caught his breath and shot a hard look at Dawson.
"How did you know?" he demanded.
"I didn't," Dave replied. "But I had a hunch it might be one of those two. It had to be somebody close to you, and—well, Freddy had already picked the one in the outer office."
"It was the one who brought you up in the elevator," Colonel Welsh said with an effort. "It's—it's things like this that almost make me lose faith. That man had been in the bureau for six years. For four years before that he was connected with Secret Service. His record was spotless. And the amazing part is that he had performed some valuable services for me. But that goes to show you the finesse of the Gestapo and Nazi agent technique. Shows you how long ago Hitler laid plans for America. I would have staked my life on Babson, but—"
The officer paused and gestured despairingly.
"But of course I would have lost my life!" he suddenly bit off. "But for an accident I'd never have found out, perhaps. And who knows what else that would have cost us? He was taking Lamb down late last night. As he opened the doors a slip of paper fell out of his pocket. Lamb caught it in mid-air, and was starting to hand it back when he saw what was on the paper. It was a bit of code, obviously jotted down in a hurry. But it was a code that only Lamb and I knew, not another soul in the world. For years he and I have been working on a code that can't possibly be broken down by any of the experts. We thought we had found it. Kept our papers on it in a safe. Only Lamb and I knew the combination—we thought."
"What happened, sir?" Freddy asked eagerly as Colonel Welsh let his voice trail off into silence. "Did Captain Lamb make the dirty beggar confess?"
The chief of U. S. Intelligence shook his head.
"He didn't have time," he said. "Babson realized instantly that he'd never in the world be able to explain his possession of that bit of copied code. His only hope was quick action, and flight. He went for his gun. Lamb didn't give me the details of the fight. He won, and Babson is dead. Then Lamb got busy. He began with the little office Babson used on the ground floor. He—It seems incredible! I thought that Lamb was crazy, or blind drunk, and making it up. But he wasn't, of course. Babson had actually installed a dictograph in our working room. The other end was in his office. The wire led out behind the files, under the corridor boards and down the elevator shaft, and under the lobby floor to his office. He could hear every word we said up there. How he learned that safe combination, we'll probably never find out. In his Washington hotel room Lamb found enough stuff to hang the man a dozen times over. Too bad we won't be able to do it. I feel like going out and shooting myself. I'm the one responsible, of course. One of my own trusted men! That's the worst of it!"
The Colonel gave a bewildered shake of his head, and groaned heavily.