Below the basement floor were a dozen rooms not high enough for a man to stand erect in. The light of day never entered. What light they received came from one main gas jet in the corridor or the occasional flash of a policeman’s pocket light as the Chinatown squad made their rounds. Save for the members of the squad, and at times a jaded police reporter, idling from the reporters’ room in the near-by Hall of Justice on a quiet night through the district with the squad sergeant, it is probable no white man save the “fiends” of the district had ever before gasped for breath in that foul den--no white man, that is, before Captain Robert Swanson, who entered there one night never to emerge. It was three days before one of the denizens of the subcellar, finally realising that the occupant of the next bunk was not in the stupor of drug but the stiffness of death, made his way with frantic hippity-hoppings to the first member of the squad he could find and reported the matter, not forgetting to whine for his ten cents for so doing. Such, in substance, were the facts in the mystery that set the city and the coast--Swanson was a notable figure in shipping circles--in a ferment for a week. For, more than the initial fact of finding the body in Chinatown’s cesspool, five days had now elapsed with not one single additional fact of consequence to clear the mystery. Suspects without number had been jailed. Every ex-convict, “fiend,” vagrant, or questionable character of the district, white, yellow, or black, male or female, had been put through the police mill. The opium dens had been emptied of their wastrels, blinking like bats in the light of day. Swanson’s past and his present life were run under a high-power lens; his servants’ and his employees’ lives and the lives of his former servants and former employees; Chief Leslie was a fellow member of the Cosmos Club with Swanson, and if any additional good to his natural police pride were necessary to spur him on, that afforded it. Every recourse that police experience could adapt or devise was applied. Always there was lacking motive: that mainspring for crime. That Swanson had by any chance been addicted to the drug habit was early dismissed. Practically every hour of his methodical life could be accounted for for months back. But in so far as his movements were concerned from the moment he left his doorstep on Wednesday evening until the body was found, he may as well have left his doorstep invested in an invisible mantle, for no living person that could be located had seen him alive. There was one peculiar circumstance. He had worn that night a heavy ulster overcoat, although the night had not been chilly, and Mrs. Swanson had remarked on it at parting. The coat was not found with the body.