"You might try Mrs. Amos Parsons," he suggested, and pointed to the telephone table in a corner of the library. "Kitty is her private secretary. No, wait," as Mitchell snatched up the telephone book and hastily turned its well-thumbed pages. "She may be with her cousins, Mr. and Mrs. Ben Potter. Here, I'll look up their number for you." Mitchell hung up the receiver in disgust a minute later. "Central declares no one answers," he explained. "Who shall we try next? Mrs. Parsons, did you say?" This time he was more successful in getting the number desired, but the reply to his question was unsatisfactory. "The butler declares Miss Baird hasn't been there since yesterday," he told his companion. "Mrs. Parsons is not at home." McLean's expression had grown serious. "We had better communicate with Charles Craige," he said. "Craige has handled Miss Baird's affairs for years, lawyer, agent, and all that. He may aid us in locating Kitty." Then with a touch of impatience, "Don't stop to look up the number of his law office--it is Main 3300." As Inspector Mitchell turned again to the telephone, McLean rose and slowly paced back and forth the length of the library. His familiarity with the furnishings and the contents of the bookcases--his taste in literature having coincided with that of Colonel Baird, who spent the last years of his life squandering a depleted fortune to gratify his craving as a collector--caused him to pay little attention to his surroundings, and he walked with head bent, his thoughts with the dead woman upstairs. Was Inspector Mitchell right--could it have been murder? Who would have reason to harm so feeble an old lady? What motive could have inspired such a senseless crime? Robbery--bah, thieves would not kill to secure books and knickknacks of doubtful value. But then what motive could have prompted suicide? Why should a woman so near the grave take her own life? Miss Baird had abhorred illness in any form; she had always had a healthy distaste for invalidism, and little patience with neurotic friends. Miss Susan Baird, of all persons, to be found dead--possibly murdered! McLean took out his handkerchief and passed it over his forehead. For the first time he grew conscious of the closeness of the atmosphere, of the musty smell which dampness sometimes engenders. Instinctively, he stopped in front of a side door which opened on a "stoop" leading to the garden which extended to the back of the house. The door resisted his attempts to open it, and he felt for the key. It was not in the lock.