"Undoubtedly he believes that Mrs. Dallas killed Maurice," thought Jen, "and that is why he refuses to confess to me. He said that I would be the first to blame him for telling all he knew, and as he is under the delusion that Mrs. Dallas is guilty, I understand now the reason of his silence. Also he said that he would never marry Isabella; which shows that he is afraid of becoming the husband of a woman whose mother has committed a crime. Poor boy, how he must suffer; and after all I must say that I approve of his honorable silence. But!" added the major to himself, "when he knows that Mrs. Dallas is innocent and that Etwald is guilty, he will then be able to marry Isabella!" On consideration Jen thought it would be best to say nothing definite to David about his discovery. If the young man, from a feeling of honor toward an unhappy woman, kept silent, the major was the last person in the world to tempt him to break it. Jen decided to merely hint to David that he knew the truth, and let the arrest of Etwald tell its own tale, and unseal the lad's lips, by showing that Mrs. Dallas was innocent. As Jen came to this conclusion, he entered his own gates, and rather to his surprise, he saw David, considerably agitated, advancing to meet him. "Inspector Arkel and Dr. Etwald are waiting for you in the library," said Sarby, rapidly. "I know it. I sent for them." "You sent for them?" "Well, why not? I wish the first to arrest the second." "Arrest Dr. Etwald! On what grounds?" "On the grounds of having murdered Maurice," said Jen, coldly. "Yes, you may look astonished, David, but it is the truth. Without your assistance I have discovered that Etwald is guilty. Also," added the major, in a kindly tone, "I know the reason of your silence." "Of ray silence?" echoed David. "You know the reason?" "Yes, and I honor you for it." "Who--who--told you?" stammered the young man, as pale as death. "Miss Dallas." "Isabella! My God!" David looked terrified. CHAPTER XX. A STRANGE REQUEST. Before Jen had time to inquire the meaning of David's strange exclamation, the young man had turned on his heel and was walking rapidly back to the house. Surprised by this behavior, and suspicious of its reason, the major called out to him to stop; but without taking any notice the young man increased his pace, and was soon lost to sight. Still marveling, Jen went after him, and on entering the library found that only Arkel was present. "Where is Dr. Etwald?" demanded the major, anxiously. "He went upstairs a few minutes ago to see your servant," replied the inspector, rising. "Alone, Mr. Arkel?" "Why no, major. Mr. Sarby was with him."