world," said Crewe.

"But she went downstairs," said the colonel. "I heard the alarm click."

"The alarm?" questioned Crewe.

"I've got a buzzer under one of the treads of the stairs," said the
colonel. "It is useful to know when people are coming up."

* * * * *

Ten minutes passed and Selby returned to say that the policeman had been
making inquiries as to whom the car belonged.

"You'd better get it away," said the colonel, "and send away your men."

"They've gone," said the other. "I wasn't taking any risks."

He disappeared to carry out the colonel's instructions, and they heard
the whine of the moving car.

Boundary unlocked his tantalus and took out a full decanter of whisky.
Without a word he poured three stiff doses into as many glasses and
filled them with soda. Each man was thinking, and thinking after his own
interests.

"Well, gentlemen," said the colonel at last. "I incline to give this
business best."

He looked up and saw the dagger which Pinto had thrown. It was still
embedded in the wall.

"It isn't enough that I should have Jack o' Judgment messing my room
about," he growled, "but you must do something to the same wall! Pull it
out and don't let me see it again, Pinto."

The Portuguese smiled sheepishly, walked to the wall and gripped the
handle. Evidently the point had embedded in a lath, for the knife did
not move. He pulled again, exerting all his strength and this time
succeeded in extracting not only the knife but a large portion of the
plaster and a strip of the wallpaper.

"You fool!" said the colonel angrily, "see what you have done--Jumping
Moses!"

He walked to the wall and stared, for the dislodgment of plaster and
paper had revealed three round black discs, set flush with the plaster
and only separated from the room by the wallpaper, which had been
stripped.

"Jumping Moses!" said the colonel softly. "Detectaphones!"

He took Pinto's knife from his hand and prised one of the discs loose.
It was attached to a wire which was embedded in the plaster and this the
colonel severed with a stroke of the knife.

"This is the business end of a microphone," he said.

"The voice!" gasped Pinto, and the colonel nodded.

"Of course. I was mad not to guess that," he said. "That's how he heard
and that's how he spoke. Now, we're going to get to the bottom of this."

With a knife he slashed the plaster and exposed three wires that led
straight down