"Do you know who he is?" she asked a detective.
"Looks like Angel Face Myers, one of Molberg's boys. Can't be sure 'till we've mugged and finger-printed him at the station."
The three men from the Nichols Agency plied the prisoner with sharp questions. He maintained a sullen silence.
"I'd guess he was taking Miss Nichols to that abandoned house at the top of the hill," one of the detectives surmised shrewdly. "I'll stay here and guard the prisoner while you fellows investigate the place. Don't let anyone get away from you."
The other two detectives disappeared into the darkness. Twenty minutes later they returned to report that they had found no one at the old house, although there was evidence of a hurried departure. The shots previously fired by the detectives had served as a warning.
Riding back to the city with the handcuffed prisoner, Penny wondered how faithfully her father's investigators had followed her movements of the evening. Had they noted her call at the Davis home or the visit she and Susan had paid to the Hamilton building?
"I suppose I've been trailed everywhere to-night," she ventured conversationally.
"You almost gave us the slip," one of the detectives told her with a smile. "In fact, you did for awhile."
"When was that?"
"Right after you left the library."