Duvall thanked him, then turned away. Although he realized that he could scarcely hope to obtain even a scanty description of the sender of the telegram from the main office, he determined to go there. First, however, he walked back toward the Mortons' apartment, and going up the steps of the brownstone house adjoining, rang the doorbell. A neat maid-servant opened the door. Duvall favored her with a smile, at the same time taking a notebook and pencil from his pocket. "I am making some corrections in the city directory," he said. "Will you please give me the names of all the persons living in this house." The girl stared at him for a moment, but his prosperous appearance, his businesslike manner, disarmed any suspicion she may have felt. "There's--there's Mr. William Perkins," she said, "and Mrs. Perkins, and Mr. Robert, that's Mr. Perkins' son, and--and Miss Elizabeth, although she's away at boarding school, and--and Emily Thompson, the cook, and--and me. My name's Mary. Mary Wickes." "Thank you, Mary," Duvall replied, entering the names carefully in his notebook. "And Mr. Perkins, the elder Mr. Perkins, I mean, is he the lawyer?" "No, sir. It's Mr. Robert that's the lawyer, sir. Mr. William Perkins is in the leather business." "Ah, yes. I see. Thank you very much indeed. And there are no boarders, or other persons whatever living in the house?" "No, sir. Not any, sir." Duvall closed his book and put it carefully in his pocket. "Now, Mary," he continued. "Just one more question. Does any one sleep in the attic?" "The attic, sir? Why, no sir. Cook and I sleep on the fourth floor, sir, but the attic isn't used, except for storage, sir. Are you going to put that in the directory too, sir?" The girl regarded him with wondering eyes. "No, Mary. Not in the directory. But we want to be sure not to omit any names, and I thought that if there was anyone living in the attic----" he paused. "No one, as I've told you. Nobody ever goes up there, so far as I know. Is that all, sir?" "Yes. That's all. Thank you. Good morning." Duvall went down the steps, and proceeded to the subway station, somewhat mystified. He had handled many curious cases in the past, many that had been notable for their intricacy, their complexity of motive and detail. But here, he felt, was a case of a very different sort, the peculiarity of which lay in its astonishing lack of clues of any sort. Usually in the past there had been motives, evidence, traces of some kind or other, upon which to build a case. Here there was nothing, except the three mysterious letters, the one equally mysterious telegram. He felt baffled, uncertain which way to turn. In rather a dissatisfied frame of mind he made his way to the telegraph office in lower Broadway. There were several clerks engaged in receiving messages. He approached one of them.