On the twenty-first of June, in the year one thousand eight hundred and ninety-four Mr. Fanks, of New Scotland Yard, detective, was walking down the Strand, between the hours of seven and eight in the evening, in the character of Octavius Rixton, of the West End, idler. It may be as well to repeat here, what is no doubt already known--that this individual led a dual existence. He earned his money as a detective, and spent it as a man about town. East of Trafalgar Square he was called Fanks; westward he was known by his real name of Rixton. But few people, were aware that the idler and the worker were one and the same. Nevertheless of necessity four or five persons possessed this knowledge, and of these one was Crate, a brother officer of Fanks, who had worked with him in many cases, and who had a profound respect for his capabilities. Fanks had obtained this ascendancy over Crate's mind by his skilful unravelling of the Chinese Jar mystery. This especial evening Rixton had cast off the name, clothes, and personality of Fanks; and in "propria persona," he was about to treat himself to a melodrama at the Adelphi Theatre. As he was passing through the vestibule, at a quarter to eight, a man came forward and touched him on the arm. To the surprise of Rixton he recognised Crate. "You mentioned that you were coming here this evening, Mr. Rixton," said this latter, who had been instructed to so address his chief on particular occasions. "And I have been waiting for the last half hour to see you." "What is the matter, Crate?" The subordinate beckoned Rixton to a quiet corner, and in a low tone said one word, which made him dismiss from his mind the idea of attending the theatre on that evening. The whispered word was "murder." "Where?" asked Fanks, assuming the detective on the instant. "Down Tooley's Alley." "Man or woman or child?" "Man I think a gentleman." "When was the crime committed?" "Between six and seven this evening." "In a house or on the street?" "In a house. The Red Star public-house." "I know it," said Fanks, with a sharp nod, "a cut-throat place at the bottom of Tooley's Alley. The assassin chose an excellent locality. Poison, steel, or bludgeon?" "The first I fancy; there are no marks of violence on the body. But you had better come and see for yourself." "I agree with you. Return to the Red Star, Crate, while I go to my rooms to change my clothes. I am Rixton at present, and I don't want to mix up my two personalities. Expect me in half an hour." Crate departed with prompt obedience, and Rixton drove off in a swift hansom to his chambers in Duke Street, St. James. In ten minutes he had assumed his detective clothes and Fanks personality; in twenty he was returning eastward; and at the expiration of half an hour he was standing at the door of the house wherein the crime had been committed. Such promptitude was characteristic of the man. Tooley's Alley is a narrow zig-zag street, which, beginning at a point in Drury Lane, twists its way through a mass of malodorous houses until blocked finally by the Red Star Hotel. It is a famous Rialto of rogues and vagabonds, for here "they most do congregate;" and here come the police, when any especial criminal is wanted by the law. An evil district with an evil name; a plague spot, which cannot be eradicated either by law or by religion. There are many such in London, and of all Tooley's Alley is the worst. It was plausible enough that a gentleman should be trapped, robbed, and murdered in this quarter; but it was more difficult to surmise what errand had brought a gentleman into so dangerous a neighbourhood. A gentleman done to death in Tooley's Alley Fanks scented a mystery.