The operative followed her to the institution, entering the door only a few moments behind her, and saw her enter a room on the second floor. A few minutes later the woman operative was surprised to see the suspect leave her room, wholly changed in appearance, the black shawl having been replaced by a dark sack suit and a black sailor hat. As the woman had that afternoon received a letter at the Post Office, it was suspected that, as a go-between, she would deliver this letter to some one. She left the building and boarded a street car. The woman operative entered a waiting automobile and followed. Again the mystery woman proved too elusive. The next morning the woman operative was up and on guard before daybreak and was enabled to trail the woman to a business establishment, where, it was learned, she was employed in clerical work. She was again dressed in the sack suit and black sailor hat, and apparently assumed the habit of a nun only upon inquiring at the Post Office for mail. The most thorough inquiries failed to reveal any additional evidence indicating this woman’s connection with enemy activities, or solve the dual character she was impersonating. It was ultimately determined to take her to the Bureau, where she might be thoroughly interrogated, which was done. Her explanations were simple but unsatisfying. However, there was no violation of the law with which she could be charged, and it was necessary to permit her to go. She moved to another hotel where the St. Louis division continued to keep her under surveillance, without, however, throwing any further light upon the mysterious letter. Other apparent clues were likewise run down in vain. The letter bears every evidence of having been a serious attempt to communicate information of more or less value to the enemy and appears to permit of further decoding through the use of some additional cipher. It is by no means sure that the ultimate code for it will not be found by some expert government man in Washington. The world little knows what marvels of unraveling secrets is done in the Intelligence work of the Government. Always the battle goes on between those trying to make codes that cannot be read by an outsider and those who say they can master any code if given time. In any case, here is a fine detective story. Little or no successful attempt was made by St. Louis Division to keep the organization’s work a secret, and in a center so large, that always is a moot question. In the first place, any large operations, like raids and drives cannot be kept secret, and in the second place, the fear created by the thought of hidden regulators has proved a valuable deterrent, as has been shown countless times. In any case, months ago the local press was “playing up” the League in many stories that named it very frankly. Since that is true, some of the anecdotes collected may be given here.