Gresham rose. A load seemed to have dropped from his shoulders. "That's white of you, Carroll! I appreciate it." "Not at all. I have no desire to cause annoyance or inconvenience where it is unnecessary. And Miss Rogers told me, with great attention to detail, just why and how it was impossible for your sister to have been anywhere except at home last night." "Evelyn's considerable of a brick, in spite of the fact that she's more or less minus in the upper story. And now, if you're really satisfied, I'll be going." The two men walked to the door together. They were about of a height; Carroll slightly the heavier of the two. "You've no idea as to the identity of the woman in the taxicab, have you, Gresham?" "No. Have you?" "None whatever; though I fancy something ought to develop in the near future. The city is discussing it pretty freely?" "The town's wild about it. They don't understand anything. It's tough on my sister. Hazel is only a kid, and I think she was in love with Warren. Well, good day, Carroll." He extended a firm hand. "Any time I can be of any help--" "Thanks, Gresham." Five minutes after Gresham's departure, Carroll was in his car, headed for the police-station. He turned the case over and over in a keen, analytic mind which had been refreshed by a night of untroubled sleep. There were a good many features about it which puzzled him considerably. While he had not expected that the trail of the mysterious midnight woman would lead to the fiancée of the dead man, the sudden dissipation of that as a clue rather threw him off his balance. He had reached the end of a trail almost before setting foot upon it. Thus far he had refused to allow himself to be worried by the strangest feature of the case--the appearance of the dead body in a taxicab which, according to its driver's story, could not have been other than empty. It was always easy to explain the disappearance of a person from an automobile; but, he figured, it was patently impossible to enter one without the driver's knowledge. He reached headquarters and closeted himself with Leverage. They plunged at once into a discussion of that phase of the case. "There are only two things which could have happened," said the chief of police slowly. "One is that some one croaked that bird Warren and shoved him into the cab while the woman was ridin' in it. The other is that he slipped into the cab and she killed him. While I ain't jumpin' on no set ideas, I have a hunch that the last one is right." "Why?" "Because the other--that idea of puttin' a dead body into a cab without the driver knowing it--it just naturally ain't possible." "Then you are quite convinced, Leverage, that Walters did _not_ know anything about it?"