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.

He made his way directly to a public telephone booth.  He telephoned the Lawrence home and asked for Evelyn Rogers.  A maid answered and informed him that Evelyn had left home fifteen minutes previously.