That evening, while he was still wondering at the enterprise of a store that could obtain a post-office box number from a government bureau at Washington, the solution of the mystery came to him in a decidedly unexpected manner. The house in which Holden was staying was old-fashioned, one of the kind that are heated, theoretically at least, by "registers," open gratings in the wall. Holden's room was directly over the parlor on the first floor and the shaft which carried the hot air made an excellent sound-transmitter. It so happened that Simmons, after having made a number of inquiries around town about the original Dave Holden, called at the boarding house that night to discover what the landlady knew about the other man of the same name, who was seated in the room above. Suddenly, like a voice from nowhere, came the statement in a high-pitched feminine voice: "I really don't know anything about him at all. Mr. Holden came here about six weeks ago and asked me to take him in to board. He seemed to be a very nice, quiet gentleman, who was willing to pay his rent in advance. So I let him have one of the best rooms in the house." At the mention of his name Holden listened intently. Who was inquiring about him, and why? There was only a confused mumble--apparently a man's reply, pitched in a low tone--and then the voice of the landlady again came clearly through the register: "Oh, I'm sure he wouldn't do anything like that. Mr. Holden is...." But that was all that the pension applicant waited for. Moving with the rapidity of a frightened animal, he secured one or two articles of value from his dresser, crammed a hat into his pocket, slipped on a raincoat, and vaulted out of the window, alighting on the sloping roof of a shed just below. Before he had quitted the room, however, he had caught the words "arrest on a charge of attempting to obtain money under false pretenses." Some two minutes later there was a knock on his door and a voice demanded admittance. There was no reply. Again the demand, followed by a rattling of the doorknob and a tentative shake of the door. In all, it was probably less than five minutes after Larry Simmons had entered the parlor before he had burst in the door of Holden's room. But the bird had flown and the open window pointed to the direction of his flight. Unfortunately for the operative the night was dark and the fugitive was decidedly more familiar with the surrounding country than Larry was. By the time he had secured the assistance of the police half an hour had elapsed, and there weren't even any telltale footprints to show in which direction the missing man had gone.