Leon hung up the receiver, hugging himself.
“The idea being——?” said Poiccart.
“These people are clever.” Leon’s voice was charged with admiration. “They haven’t cut the wires—they’ve simply tapped it at one end and thrown it out of order on the exchange side.”
“Phew!” Manfred whistled. “You deceived me—you were talking to Oberzohn?”
“Captain Monty and Lew Cuccini. They may or may not be deceived, but if they aren’t, we shall know all about it.”
He stopped dead. There was a knock on the front door, a single, heavy knock. Leon grinned delightedly.
“One of us is now supposed to open an upper window cautiously and look out, whereupon he is instantly gunned. I’m going to give these fellows a scare.”
He ran up the stairs to the top floor, and on the landing, outside an attic door, pulled at a rope. A fire ladder lying flat against the ceiling came down, and at the same time a small skylight opened. Leon went into the room, and his pocket-lamp located what he needed: a small papier-mâché cylinder, not unlike a seven-pound shell. With this on his arm, he climbed up the ladder on to the roof, fixed the cylinder on a flat surface, and, striking a match, lit a touch-paper. The paper sizzled and spluttered, there was a sudden flash and “boom!” a dull explosion, and a white ball shot up into the sky, described a graceful curve and burst into a shower of brilliant crimson stars. He waited till the last died out; then, with the hot cylinder under his arm, descended the ladder, released the rope that held it in place, and returned to his two friends.
“They will imagine a secret arrangement of signals with the police,” he said; “unless my knowledge of their psychology is at fault, we shall not be bothered again.”
Ten minutes later there was another knock at the door, peremptory, almost official in its character.