He took the key that the chief warder had given him, unlocked the doors and slid them back. They were looking into a bare, clean apartment with whitewashed walls. Across the ceiling ran two stout oak beams, and between them three stubby steel bars. The prisoner frowned as Elk walked to a long steel lever near one of the walls. “Watch, Frog!” he said. He pulled at the lever, and the centre of the floor divided and fell with a crash, revealing a deep, brick-lined pit. “See that trap . . . see that ‘T’ mark in chalk? That’s where a man puts his feet when the hangman straps his legs. The rope hangs from that beam, Frog!” The man’s face was livid as he shrank back. “You . . . can’t . . . hang—me,” he breathed. “I’ve done nothing!” “You’ve killed a man,” said Elk as he pulled the doors to and locked them. “You’re the only fellow we’ve got, and you’ll have to suffer for the lot. Are them beans growin’?” The prisoner raised his shaking hand to his lips. “I’ll tell you all I know,” he said huskily. Elk led him back to his cell. An hour later, Dick was speeding back to his headquarters with considerable information. His first act was to send for Joshua Broad, and the eagle-faced “tramp” came cheerfully. “Now, Mr. Broad, I’ll have your story,” said Dick, and motioned the other to be seated. Joshua seated himself slowly. “There’s nothing much to tell,” he said. “For a week I’ve been getting acquainted with the Frogs. I guessed that it was unlikely that the bulk of them would be unknown to one another, and I just froze on to the first I found. Met him in a Deptford lodging-house. Then I heard there was a hurry-up call for a big job to-day and joined. The Frogs knew that the real attack might be somewhere else, and on the way to Scotland Yard I heard that a party had been told off to watch for Litnov at Wandsworth.” “Did you see any of the big men?” Broad shook his head. “They looked all alike, but undoubtedly there were two or three section leaders in charge. There was never any question of rescuing. They were out to kill. They knew that Litnov had told all that he knew, and he was doomed—they got him, I suppose?” “Yes—they got him!” said Dick, and then: “What is your interest in the Frogs?” “Purely adventitious,” replied the other lazily. “I’m a rich man with a whole lot of time on my hands, and I have a big interest in criminology. A few years ago I heard about the Frogs, and they seized on my imagination. Since then I’ve been trailing them.” His gaze did not waver under Dick Gordon’s scrutiny.