The letter was signed by the ambassador in person. It had arrived at Nick Carter’s house during the afternoon of the preceding day. It was now approaching eleven o’clock in the forenoon of the first day in June. Nick Carter, during his varied career, had had more or less experience with matters diplomatic, and was accustomed to the somewhat stilted phrases and mannerisms which all ambassadors and ministers regard it as necessary to employ; but it was unusual that an ambassador should so far commit himself as to make a covert charge against one of his own household. For the detective could read the letter in no other way than that the gentleman—he had been so described—now waiting in the library to see him was under suspicion. But suspicion of what? Nick Carter had no idea as to that. Something had gone wrong with the Russian ambassador, which required the services of an expert investigator, and for some reason not given, it had not been deemed advisable to call in the services of the regular Secret Service of the United States Government. Somebody as yet unknown to the detective, but doubtless a person high in authority in Washington, had recommended Nick Carter to the ambassador; hence the letter. Chick returned while the detective was turning these things over in his mind, and he raised his eyes expectantly when his first assistant entered the room. “There is nothing remarkable, or even interesting, about the chap that I can discover,” said Chick, in reply to the interrogative glance. “He is just a plain, common type of the Russian army officer who has been appointed military attaché to this country through influence at court. He is less than thirty years old and more than six feet tall. I should say that he is not overburdened with brains. “He belongs to the type that gets into no end of trouble through ignorance, stupidity, pride, arrogance, and all that sort of thing, but does not seem malicious at all. He is fair-headed, blue-eyed, rather good-looking—some women would call him handsome—and all in all, is rather a likable chap, I imagine. He ranks as colonel in the Russian army, and the card he sent up to you is not his own, which fact he took pains to explain the minute I entered the library where he is waiting.” “This card is not his own?” said Nick, picking it up and glancing at it again. He had barely noticed it when Joseph gave it to him. “No. His name is——” “Why did he send me a card not his own?” “He said it was done by mistake, and that he did not discover it until Joseph had left the room to take it to you. I think he told the truth about that. He spoke as if it were the truth.” “Very likely. The name on this card means nothing at all to me—or to him probably. No name was mentioned in the letter from the ambassador. What is his name?” “He is Colonel Alexis Turnieff.”