Carroll, well versed in applied psychology, knew that in such a combination of facts there lay an important clue. He was well satisfied that Naomi Lawrence had been satisfied that she was not to be alone that night!
Arguing with himself from that premise, the conclusion was inevitable: she knew that her husband would return from Nashville at midnight. She did not wish anyone—even Evelyn, to learn that he had done so. Therefore she got Evelyn out of the house!
The conclusion developed a further train of reasoning—one which Carroll did not at all relish, but which he faced with frank honesty. If he was right in his argument—then Naomi Lawrence had known of the murder before it was committed!
He shrank from the idea, but it would not down. He was not ready to admit its truth—but there was no denying its logic. There was something inexpressibly repugnant in the thought. He infinitely preferred to believe that Naomi hated her husband—was miserable with him—he preferred that to the idea that they were accomplices in the murder of a prominent young man.
Then, too, there were the strange visits of William Barker, former valet to Warren, to the home of the Lawrences. There was no doubt remaining in Carroll's mind that Barker knew a very great deal about Warren's murder. That being the case it was fairly well established that he was cognizant of the Lawrences' connection with the crime.
Carroll had started off with the idea that someone, in addition to the woman in the taxi-cab, had been instrumental in ending Warren's life. Here, following a casual line of investigation, he had uncovered the tracks of two men, both of whom he was convinced knew more about it than they had cared to tell.
Both men—Barker and Lawrence—had acted peculiarly under the grilling of the detective. The former had been surly and non-informative, only to leap eagerly upon the first verbal trend which tended to throw suspicion upon a person whom Carroll knew—and whom Carroll knew Barker knew—was innocent. Gerald Lawrence, on the other hand, had been downright antagonistic until he made the startling discovery that his supposed alibi was no alibi at all—at which his attitude changed from open hostility to something closely akin to suppliance.
Then, too, there was the danger of injuring an innocent man because of his inability to prove an alibi. If Lawrence's story was true, it was perfectly natural that even in a condition of intoxication he would maintain his instinct for concealment of a personal weakness. The chances were then that no one had seen him either in Nashville—after the four o'clock train had left, or on the two a.m. train homeward bound.
Matters could not right themselves in Carroll's mind. He knew one thing, however—Evelyn Rogers was a wellspring of vital information. The very fact that she talked inconsequentialities incessantly—and occasionally let drop remarks of vital import—made her the more valuable. He knew that he had not seen the last of the seventeen-year-old girl. And he felt a consuming eagerness to be with her again, for now he had a definite line of investigation to pursue.
He slept soundly that night, and the following morning dropped in on Leverage. The Chief of Police had a little information—with all of which Carroll was already familiar. He told Carroll that Lawrence had been in Nashville and that he had checked out of the Hermitage hotel in time to catch the four o'clock train on the afternoon preceding the murder. Carroll satisfied Leverage by accepting it as information, made sure that nothing else of importance had developed, requested Leverage to ask the Nashville police to determine whether Lawrence had been seen in Nashville after 4:30 p.m.—if necessary to send one of his own men there—and left headquarters.