“I don’t know!” he cried out, as one in an extremity of uncertainty. “It must be poison--it must have been--murder!” He pronounced the last word in a gasping way--as if afraid to suggest it but forced to do so. Hendricks looked at him with a slight touch of contempt in his glance, but seeing this, Dr. Harper interjected: “The Examiner is regretting the necessity of thrusting his convictions upon you, but he knows it must be done.” “Yes,” said Crowell, more decidedly now, “I have had cases before where murder was committed in such an almost undiscoverable way as this. Never a case quite so mysterious, but nearly so.” “What is your theory of the method?” asked Elliott, who was staggered by the rush of thoughts and conclusions made inevitable by the Examiner’s report. “That’s the greatest mystery of all,” Crowell replied. He was quite calm now--apparently it was concern for the family that had made him so disturbed. “Poison was not taken by way of the stomach, that is certain. Therefore, it must have been introduced through some other channel. But we find no trace of a hypodermic needle--” “How utterly ridiculous!” Eunice exclaimed, her eyes blazing with scorn. “How could any one get in to poison my husband? Why, we lock all our doors at night--we always have.” “Yes’m--exactly, ma’am,” Crowell began, rubbing his hands again; “and now, please tell me of the locking up last night. As usual, ma’am, as usual?” “Precisely. Our sleeping rooms are those three,” she pointed to the bedrooms. “When they are locked, they form a unit by themselves, quite apart from the rest of the apartment.” Dr. Crowell looked interested. The apartment faced on Park Avenue, and being on the corner had also windows on the side street. Front, enumerating from the corner and running south, were the dining-room, the large living-room, and the good-sized reception hall. Directly back of these, and with windows on a large court, were the three bedrooms, Eunice’s in the middle, Sanford’s back of the hall, and Aunt Abby’s back of the dining-room. Aunt Abby’s room was ordinarily Eunice’s boudoir and dressing-room, but was used as a guest chamber on occasion. These three bedrooms, as was shown to Examiner Crowell, when locked from the inside were shut off by themselves, although allowing free communication from one to another of them. “Lock with keys?” he asked. “No,” Eunice replied. “There are big, strong, snap-locks on the inside of the doors. I mean locks that fasten themselves when you shut the door, unless you have previously put up the catch.” “Yes, I see,” and Crowell looked into the matter for himself. “Spring catches, and mighty strong ones, too. And these were always fastened at night?” “Always,” Eunice declared. “Mr. Embury was not afraid of burglars, but it was his life-long habit to sleep with a locked door, and he couldn’t get over it.”