In the mean time, the Post-Office Department had been informed of these facts, and an experienced and skilful police officer in Chicago was appointed Special Mail Agent to investigate the matter. He very soon came to the conclusion that whoever the other guilty persons might be, B. was "one of 'em" to all intents and purposes. As we have before stated, B. had said that one of the leaders was in New York, and at the request of the company's attorney, B. wrote a letter to him. The Chief of Police of New York was written to, and requested to station an officer at the post-office to watch for and arrest the party who should call for the letter, but during the time which elapsed between the arrival of the letter and the officer who was to watch outside the post-office, the letter disappeared, and even before any one connected with the New York post-office had been apprised of the arrangement. Four days afterwards, B. informed one of the company's attorneys that the man in New York had received the letter and sent him a verbal answer to the effect, that he had better write no more by mail, "as the letters might get lost." Mr. P., the Chicago police officer, went in company with a lawyer to New York, with the design of finding the man to whom the letter was addressed. Their efforts, however, though assisted by the Chief of Police, and the Special Agent for the New York district, were unavailing. It was ascertained that he had paid his passage to Liverpool on the ship Washington, but having been asked a casual question by one of the officers of the vessel, concerning his relationship to a certain Englishman, he had forfeited his passage-money, and disappeared. Having returned to the West, Mr. P., the government Agent, determined to arrest B., which he effected, and, without his knowledge, obtained possession of his boots, which had already supplied such important evidence against him. He displayed much virtuous indignation, and talked largely of his wealth, respectability, and high standing in society; but all this availed him nothing, and he was committed to jail. Although he had arrested B., yet Mr. P. doubted whether he had sufficient evidence to convict him, and determined to condemn him out of his own mouth. Accordingly he made arrangements with a deputy sheriff of Milwaukie, to play the part of prisoner, and thus to obtain the rascal's confidence. Agreeably to this arrangement, when B. entered the prison, he found the deputy sheriff already in his cell, apparently a fellow victim to the demands of justice. For about four weeks this gentleman was most of the time in the cell with B., representing himself as an "express robber;" conducting himself in such a turbulent manner that B. supposed the time of his absences was passed in the dungeon.