"In that case, sir," there was a steely glint in Mitchell's eyes which betokened trouble, "I shall send for a locksmith and have the bolt forced." "Wait," Foster laid a restraining hand on Whitney's shoulder as the latter made a hasty step in the detective's direction. "I assure you, Mitchell, that the so-called studio is Mr. Whitney's workshop; he is, as you no doubt know, an inventor." Whitney opened his mouth to speak, then closed his jaws with a snap. "Mr. Whitney is now engaged upon a most important invention. It is quite natural that he does not wish...." "It is hardly a matter of wishes, Mr. Senator," broke in Mitchell. "A murder has been committed here, and it is imperative that everything be done to apprehend and convict the criminal." "Ha!" Whitney's snort was almost a triumphant challenge. His altered demeanor did not escape the shrewd eyes watching him so keenly. "So you think I murdered Spencer?" "I have not said what I think," retorted the detective brusquely. "Come, sir, we are wasting time; take me over your studio at once." Whitney's haggard face reddened with anger; twice he opened and shut his mouth, then thinking better of his first impulse, he turned on his heel. "Follow me," he directed ungraciously. As he stepped toward the doorway he looked back and encountered Miller's intent gaze. The Captain's gray eyes, their devil-may-care sparkle dampened by anxiety for Kathleen, broad forehead, and firm mouth inspired confidence. He looked a man whose word could be relied on. Whitney, harassed by conflicting doubts, and agonizing apprehensions, acted on impulse. "Come with us, Captain. We'll be right back, Kiametia; you and Foster wait for us here." By common consent the three men avoided the elevator and walked up stairs. On reaching the attic, Whitney made at once for his studio and inserting keys in the double lock turned the wards, and opened the door. "Go in," he said, and waited until the two men had preceded him in the room, then entered and closed the door, shooting the inner bolt. The detective looked around as the faint click of the metal caught his ear. "Force of habit," explained Whitney. "Hurry and make your examination, Mitchell; I wish to rejoin my friends downstairs as quickly as possible. Have a seat, Captain?" But Miller declined, and stood watching Mitchell as he made a thorough search of the apartment. Nothing escaped his attention, and such furniture as the room boasted was minutely scrutinized, even the Cooper Hewitt lights and cylinder arc lights being switched on to assist in the examination. Models, large sink, darkroom, cabinets, tool chest, drawing tables, and small chemical laboratory were subjected to a thorough search. Miller's silent wonder grew; nowhere did he perceive a model resembling a camera, or the camera itself.