Also, it was perfectly plain to Carroll that at the outset of his conversation Lawrence had been smugly satisfied that he was possessed of a perfect alibi.  It was only under Carroll’s merciless grilling that he had been brought abruptly to realization that he had no alibi whatever.  The same logic applied there, as in Leverage’s theory that Barker’s arrest would be an excellent strategic move.  All Carroll had to do now was to arrest Lawrence for Warren’s murder—­and the burden of proof would have been shifted from the shoulders of the detective to that of the suspect.  It would then devolve upon Lawrence to prove an alibi that Carroll knew perfectly well he could not prove—­save by merest accident.

But that was a procedure which Carroll abhorred.  Those were police department methods:  wholesale arrests in the hope of somewhere in the net trapping the prey.  Such a course was at the bottom—­and Carroll knew it—­of an enormous number of convictions of innocent men.  And Carroll had no desire to injure Lawrence provided Lawrence was free of guilt in this particular instance.  He didn’t like the man—­in fact his feelings toward him amounted to a positive aversion.  But through it all he tried to be fair-minded—­and he could not quite rid himself of the picture of Naomi Lawrence—­Carroll was far from impervious to the appeal of a beautiful woman.

So much for the probable truth of Lawrence’s story.  The reverse side of the picture presented an entirely different set of facts.  There was not alone the strange procedure of checking out of the big hotel at four o’clock in the afternoon when he intended catching an early morning train:  but there was the information so innocently dropped by the loquacious Evelyn Rogers regarding Naomi’s actions on the night of the murder.

According to Evelyn, her sister was an intensely nervous woman:  one who stood in fear of being alone at night.  And yet this sister had volunteered the suggestion that Evelyn spend the night with Hazel Gresham when her husband was supposed to be out of the city.

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.