“It was Dr. Letheny,” repeated O’Leary quietly. “I knew it!” cried Corole. “I knew it!” No one looked at her. Our eyes were without exception fastened upon O’Leary’s face. “How do you know?” I said at last. O’Leary glanced about the room in indecision, then he shrugged. “As well here as anywhere,” he said. “How did I know that it was Letheny? Why did not Higgins rouse the place? Because he saw the head doctor in this room. Why was there need to hunt for the radium? Because that man who hid the stuff was dead; Dr. Letheny, disturbed about the ugly business, afraid of being caught with it in his possession, hid the thing in the loud speaker, thinking no one saw him. And only Higgins knew where it was, and Higgins, terrified at what he had seen, was afraid to tell for he knew that someone—_someone_ had come upon Letheny and killed him and Higgins hoped to escape the same fate. And since there were—others desiring the radium, a hunt was made for it. A search that was finally successful.” His clear gray eyes went from Corole to Hajek. “But just as Dr. Letheny was about to leave the room another man came upon the scene, determined to take the radium for himself. Then—I don’t know exactly what happened but the two men struggled and in the struggle Dr. Letheny’s head struck with such force that it killed him—_this_”—he crossed the room to the massive, square-cornered lavatory. “I am sure of that,” went on O’Leary, “for I examined it before a thing in the room had been touched. The other man, frightened perhaps, knowing that he was in desperate danger of being charged with murder, dragged Dr. Letheny’s body into that closet, locked the door and got rid of the key, hoping to postpone the discovery of Dr. Letheny’s death for as long as possible and thus cover his own tracks. But first he found that the radium was not to be found and knew that Letheny must have hidden it somewhere in the room. He did not dare search for it then, he would have to return. He retreated by the way he had come, through the window, there, and—and crawled through the window of his own room in the hospital in time to answer Miss Keate who, by that time, was pounding on the door.” His eyes went to Dr. Hajek, whose face was quite ghastly. O’Leary forestalled the words on Dr. Hajek’s lips. “Not now,” he said sternly. “You will have plenty of time to talk—later.” “Then—then you feel sure it was Dr. Letheny who killed Jackson?” asked Dr. Balman incredulously.