"He will do so at his own risk," cried Ellis, promptly. "And you may be sure he will never learn the truth from me until it can be told with safety to Mrs. Moxton. Leave Busham to me. I shall know how to deal with him. In some way or another we must clear up this mystery, and exonerate Mrs. Moxton. If there was only some clue." Janet and Laura looked meaningly at one another. "There _is_ a clue, although it is only a slight one," said Miss Gordon, hesitatingly. "To the identity of the murderer?" "No, but a clue which may lead to his discovery. When Laura was lying in a faint, the man who stabbed Edgar robbed him of his pocket-book." "But how could he do that without Moxton recognising him?" asked Ellis. "You know that Moxton did not die at once, but lived long enough to scrawl those blood signs on his arm denouncing Zirknitz. Now, I know that your brother is innocent, as he has established an _alibi_ with the assistance of his landlady, Mrs. Pastor." "I cannot explain that, doctor, but undoubtedly Edgar thought that Rudolph stabbed him, and so wrote on his arm to let Laura know." "You can read the cryptogram, I presume, Mrs. Moxton?" "Oh, yes, I know the signs very well. Janet taught them to me, and I showed them to Edgar for amusement. He, no doubt, wished me to know that Rudolph had stabbed him, but why he used the signs I cannot say. He hated Rudolph always, and would have got him into trouble if he could." "Well," said Ellis, after a pause, "I can conceive no reason why he acted as he did. I don't suppose the truth will ever be revealed. But about this pocket-book, Mrs. Moxton. How do you know that the murderer took it?" "I only think so. It was a red Morocco pocket-book with Edgar's initials on it in gold. He had it when he went out that night, and I saw him put it into his breast pocket. When Janet came to Pimlico I asked her if she had seen it, as I thought that there might be some bank-notes in it, and we needed money badly." "Did he carry money in it?" "Yes, when he had any." "On that night were there any notes in the pocket-book?" "I cannot say. Rudolph declares that he won twenty pounds from Edgar on that night. Edgar could not pay him save with an I.O.U., so I don't think there could have been money in the book." "Then why should the assassin steal it?" "Why, indeed!" echoed Janet, who had been silent for some time; "that is what we wish to find out. As Edgar's jewellery was untouched, robbery could not have been the motive of the crime. I believe myself that the pocket-book must have contained some papers of value to the murderer. No person but he could have taken it, for I examined very carefully the clothes Edgar wore when he was killed, and could not find the pocket-book. Dr. Ellis," said Janet, earnestly, "it seems to me that if you can find that book, you will be able to lay hands on the criminal."