They stopped at last before a small, detached house near the outskirts of the city. The house seemed dark and deserted.
Morgan began to wonder if he had been wise in accompanying the men, but he quickly decided that there could be little or no reason for doing personal injury to him, and so he unhesitatingly followed Cavendale up the steps, while Harrigan came behind.
The cab rumbled away.
Cavendale pressed the push-button of the electric doorbell in a peculiar manner. After a time there sounded from the inner side of the door an odd knocking. Cavendale answered in a similar manner.
There was a sound of shooting bolts, but the rattle of a chain followed, and the door was opened only a short distance. Plainly the chain was still on.
Cavendale whispered to some one within. The door closed again, the chain rattled once more, the door re-opened, and into the house of mystery they walked.
The hand of Cavendale guided Dade through the dark hall, through a room beyond and finally into still another room, which was dimly lighted.
"Here we are," said Cavendale, with affected cheerfulness. "Let's have these lights up. The chief was abed, but he'll be down directly."
The lights were turned up. The room was plainly furnished, and had but one window. That window was so heavily curtained that no gleam of light could be seen from it by any one on the outside.
Hagan pretended to joke and talk in a lively manner, but his jokes were forced and mirthless.