KETCHEL PLOT IS UNFOLDEDPolice Received Letter from Woman Telling of Alleged Conspiracy to Rob Dead Fighter.Springfield, Mo., Oct 29.—A letter received by the chief of police of Springfield signed Mrs. Maud Nugget and mailed In Salt Lake City purports to give details of an alleged conspiracy hatched by Walter Dipley and Mrs. Goldie Smith to rob and attack Sianley Ketchel, the middleweight champion pugilist, who was shot and killed near Conway, Mo., October 16.Mrs. Nugget asserts that the Smith woman wrote her of th.? plans against Ketchel and the chief of police has wired the officials at Salt Lake City to learn the Identity of Mrs. Nugget j and If possible gain possession of the Smith letter if it exists.