Sure enough, just before leaving for the station that afternoon, Williams found out from his ally at the Vanderbilt that the countess had slipped a folded and addressed newspaper into the mail box in the lobby. She had then paid her bill and entered a taxi, giving the chauffeur instructions to drive slowly through Central Park. Sibert, the operative who was trailing her, reported that several times she appeared to be on the point of stopping, but had ordered the taxi driver to go on--evidently being suspicious that she was followed and not wishing to take any chances. Of this, though, Williams knew nothing--for a glance into one of the cars on the Congressional Limited had been sufficient to assure him that his prey was aboard. He spent the rest of the trip in the smoker, so that he might not run into her. In Washington, however, a surprise awaited him. Instead of returning at once to Brickley Court, the countess checked her bag at the station and hired a car by the hour, instructing the driver to take her to the Chevy Chase Club. Williams, of course, followed in another car, but had the ill fortune to lose the first taxi in the crush of machines which is always to be noted on dance nights at the club, and it was well on toward morning before he could locate the chauffeur he wanted to reach. According to that individual, the lady had not gone into the club, at all, but, changing her mind, had driven on out into the country, returning to Washington at midnight. "Did she meet anyone?" demanded Williams. "Not a soul, sir. Said she just wanted to drive through the country and that she had to be at the Senate Office Building at twelve o'clock." "The Senate Office Building?" echoed the operative. "At midnight? Did you drop her there?" "I did, sir. She told me to wait and she was out again in five minutes, using the little door in the basement--the one that's seldom locked. I thought she was the wife of one of the Senators. Then I drove her to Union Station to get her bag, and then to Brickley Court, where she paid me and got out." The moment the chauffeur had mentioned the Senate Office Building a mental photograph of Senator Lattimer had sprung to Williams's mind, for the affair between the countess and the Iowa statesman was public property. Telling the chauffeur to wait in the outer room, the operative called the Lattimer home and insisted on speaking to the Senator. "Yes, it's a matter of vital importance!" he snapped. Then, a few moments later, when a gruff but sleepy voice inquired what he wanted: "This is Williams of the Secret Service speaking, Senator. Have you any documents of importance--international importance--in your office at the present moment?" "No, nothing of particular value. Wait a minute! A copy of a certain report to the Committee on Foreign Relations arrived late yesterday and I remember seeing it on my desk as I left. Why? What's the matter?"