"By the way, who is this Miss Thornton?" asked Douglas. "And what does she look like?" "She is a cousin of Mrs. Truxton, of Georgetown"--Douglas whistled in surprise; Brett glanced at him sharply, then continued: "I am told she is Miss Carew's most intimate friend, although about five years older. Miss Thornton must be about twenty-three. She is tall and dark, and has the most magnificent blue eyes I have ever seen in a woman's head." Douglas drew in his breath sharply. "It must be the same girl whom I knew in Paris, but I had no idea then that she was related to old family friends of mine in Georgetown." He changed the conversation abruptly. "Come, Brett, what theory have you formed?" he asked again with more emphasis. "I think both Winthrop and Hamilton have a guilty knowledge of Senator Carew's death, but how deeply Winthrop is implicated we have yet to learn." "But the motive?" argued Douglas. "It is highly improbable that Winthrop killed the Senator because he discharged a worthless servant." "If we could find that letter which I am convinced the Senator was writing when Winthrop entered the room yesterday afternoon, we would know the motive fast enough," retorted Brett. "Have you searched Carew's belongings?" "Yes, all of them, and all the furniture in his bedroom, sitting-room, and bath, as well as the rooms on this floor; but I couldn't find a trace of it. I have also thoroughly searched his office at the Capitol." "Did you think to examine the landau? The Senator might possibly have tucked it under the carriage seat." "I thought of that, and examined the interior of the carriage, but there is no possible place where a letter could be concealed. The carriage has recently been reupholstered in leather and there's no crack or tear where an envelope could slip through." "Have you inquired at the different messenger services in town?" "Yes, but there is no record at any of their offices that Senator Carew sent for a messenger to deliver a note yesterday afternoon or night. I also sent word to the post-office officials asking to have an outlook kept, and a search made for a letter franked by Senator Carew and postmarked yesterday." "It's exceedingly doubtful if you get any results from that quarter, when you don't know when or where such a letter was posted or to what city it was addressed." "The frank may help," Brett glanced at the clock. "Eleven-thirty--I must be going." He rose. "Did you meet with any success, Mr. Hunter, in the inquiries you said you would make this afternoon?" "In a way, yes. Winthrop was at the Alibi Club, taking supper with Captain Stanton. But Julian Wallace, who was one of the party, told me that Winthrop left the club about twelve-thirty." Brett whistled. "And he did not reach this house until three hours later! I am afraid friend Winthrop will have much to explain when he recovers his senses."