A close examination of the finger-marks showed a white circle, centered with a ragged dot of blood near the knuckle; this had undoubtedly been caused by a wart on the hand of the assassin. It was this fact that had attracted and interested Dyke Darrel, and what he intended showing his friend Harry Bernard. The moment Harry laid his hand against the print on the handkerchief the detective made a startling discovery. Not only did the hand of Harry Bernard fit the bloody stain exactly, but a large wart near the knuckle of the little finger fell exactly against the spot that dotted the center of the white circle. A feeling of unutterable horror filled the mind of Dyke Darrel at that moment. Harry Bernard had been his friend for years, and he had always found him upright and true. But what meant this horrible revelation of the handkerchief? Could it be possible that another had the same-sized hand and a wart near the knuckle of the little finger? It was not likely. Dyke Darrel came to his feet, with cold perspiration oozing out upon his brow. Before him sat Harry Bernard, smiling gently, and yet he had a devil in his heart--THE DEVIL OF ASSASSINATION! CHAPTER VIII. A PLUNGE TO DEATH. For some moments neither man spoke. Harry Bernard noticed that his friend was deeply moved, and he seemed to wonder at the cause. At length he said: "Dyke, what is it?" "Nothing, only---" "Well, speak out," as the detective hesitated. "It is strange that your hand should so exactly fit the marks on the handkerchief, Harry." "Well, yes," admitted the youth; "I hope you didn't imagine, however, that _I_ had a hand in this railway robbery and murder?" At the last Harry Bernard laughed lightly. Dyke Darrel did not seem to relish the young fellow's lightness, and only frowned. "This is not a laughing matter, Harry Bernard," said the detective, sternly. "Well I should say not. If you have a serious thought that I could do such a deed, Dyke, place me under arrest at once." There was an expression of rebuke on the face of Bernard as he uttered the last words. He did not look like a criminal, that was certain, and after a moment Dyke Darrel felt ashamed of his suspicions. "Never mind, Harry, I could not help feeling shocked. Let it pass; I will not wrong you by suspicion. But you will admit that it was a strange thing, your hand fitting so perfectly." "Not at all. Put your own hand here," returned Bernard. Dyke Darrel did so, but it was not so near a fit as Harry's. It was not the size of the hand, but the imprint of the wart that had so startled the detective. Harry had not discovered the true cause of his friend's excitement, and the detective concluded to say nothing about it then. Time was flying. The midnight express would soon leave the city.