That telephone conversation caused another tumult at police headquarters. The chief bellowed his orders, then ran with Verbeck and Muggs to the former's roadster, which was in readiness at the curb. With Verbeck at the wheel, the powerful car dashed through the streets toward the museum, and behind it came half a dozen police department autos filled with detectives.
They reached the museum, left the cars and hurried to the entrance. One of the men inside unlocked and opened the door.
"They are still unconscious, chief!" he reported. "Looks to me as if they had been doped."
The police surgeon made a swift examination.
"They have been drugged," he announced, "and pretty badly, at that. I'll have to get busy on them at once, or we'll have dead men on our hands."
"Bring them around as soon as you can," the chief said. "I want to hear what they've got to say. And you men search the entire building! We'll look into this! One of you call up the superintendent of the museum and get him down here. Lively!"
The officers scattered throughout the big building, turned on all the lights, and began their search. They found the unconscious guards on the upper floor and carried them below for the police surgeon to work on. The surgeon sent in a call for his assistants.
Policemen who searched the statuary hall discovered the open trapdoor. They got up into the attic, and investigated there, and found nothing except dust and footprints in it. Down to the first floor they went to report this.
Verbeck and Muggs hurried to the attic and investigated for themselves.
"Very simple," Verbeck said. "Some member or members of the gang got up here during the day, remained in hiding until night, and then got down and handled the guards and officers."