"It is a theory worth thinking about," said Bryant, who was beginning to appreciate his visitor very much. "And now, Mr Davis, the name of the man whom your sister met in the empty house?" "I have kept that to the last, to surprise you. You will know the name, but I don't suppose you ever came across the man. It was Major Hugh Murchison." At this startling announcement, the Inspector literally jumped from his chair. "But I do know Major Hugh Murchison," he cried. "He was in my office not so very long ago. Let me see, when was it?" He turned to his diary and verified the date, and gave it to Reginald Davis. It was longer back than he thought. "And you have not seen him since that day?" "No," answered the Inspector. "Wait a moment till I ring up my friend Parkinson. I couldn't undertake the job he called on, as it was quite a private matter. I handed it over to Parkinson." He rang up his old friend and former colleague. Davis could gather enough from the conversation on Bryant's side to be sure that a considerable interval had elapsed since Parkinson had seen his client. Bryant sat down in his chair. "Mr Davis, I cannot say how much obliged I am to you for your visit, and the information you have given me. Now, I know a great deal more than you do about the proceedings and movements of Major Murchison, I know on what business he was engaged, in addition to that little matter of your sister's. I will go into the inquiries concerning yourself, and please hold yourself at my disposal, give me an address where I can communicate with you readily." Davis did so, and said good-bye to the Inspector. After he had left, Bryant gave instructions he was not to be disturbed for an hour. And during that hour he did the hardest bit of thinking he had ever done in his life. And now that Davis had mentioned it, the man did bear a superficial resemblance to Hugh Murchison. CHAPTER TWENTY THREE. It was a very hard nut he had to crack. Thanks to his peculiar position, he was in possession of reliable and exclusive information from more than one quarter. He held several threads in his capable hands, but would he be able to weave them into a net wide enough for his purpose? His recent interview with Davis had established the fact that four persons were connected with the mystery of Cathcart Square--Davis himself, Caroline Masters (the elder sister), Iris Deane (the younger sister), and, most important of all, Hugh Murchison. He dismissed, for the moment, the first three from his mind. But Hugh Murchison, with his resemblance to Reginald Davis, was the connecting link between them and another set of actors.