"The most audacious crime of my remembrance." Dyke Darrel flung down the morning paper, damp from the press, and began pacing the floor. "What is it, Dyke?" questioned the detective's sister Nell, who at that moment thrust her head into the room. Nell was a pretty girl of twenty, with midnight hair and eyes, almost in direct contrast with her brother, the famous detective, whose deeds of cunning and daring were the theme of press and people the wide West over. "An express robbery," returned Dyke, pausing in front of Nell and holding up the paper. "I am sorry," uttered the girl, with a pout. "I shan't have you with me for the week that I promised myself. I am always afraid something will happen every time you go out on the trail of a criminal, Dyke." "And something usually DOES happen," returned the detective, grimly. "My last detective work did not pan out as I expected, but I do not consider that entirely off yet. It may be that the one who murdered Captain Osborne had a hand in this latest crime." The girl reeled, and clutched the table at her side for support. The name uttered by her brother was that of a friend of the Barrels, a man of family, and one who had been in the employ of the express company for many years. No wonder Nell Darrel was shocked at learning the name of the victim. "You see how it is, Nell?" "Yes," returned the girl, recovering her self-possession. "I meant to ask you to forego this man-hunt, but I see that it would be of no use." "Not the least, Nell," returned Dyke, with a compression of the lips. "I would hunt these scoundrels down without one cent reward. Nicholson was my friend, and a good one. He helped me once, when to do so was of great inconvenience to himself. It is my duty to see that his cowardly assassins are brought to justice." Even as Dyke Darrel uttered the last words a man ran up to the steps and opened the front door. "I hope I don't intrude," he said, as he put his face into the room. "No; you are always welcome, Elliston," cried Dyke, extending his hand. The new-comer accepted the proffered hand, then turned and smiled on Nell. He was a tall man, with smoothly-cut beard and a tinge of gray in his curling black hair. Harper Elliston was past thirty, and on the best of terms with Dyke Darrel and his sister, who considered him a very good friend. "You have read the news?" Elliston said, as his keen, black eyes rested on the paper that lay on the table. That was the heading to the article announcing the assassination of the express messenger. The train on which the deed had been committed, had left Chicago at ten in the evening, and at one o'clock, when the train was halted at a station, the deed was discovered. Arnold Nicholson was found with his skull crushed and his body terribly beaten, while, in the bloody hands of the dead, was clutched a tuft of red hair. This went to show that one of the messenger's assailants was a man with florid locks. Leaving Nell and Mr. Elliston together, Dyke Darrel hastened to the station. He was aware that a train would pass in ten minutes, and he wished to enter Chicago and make an examination for himself. The detective's home was on one of the many roads crossing Illinois, and entering the Garden City—about an hour's ride from the Gotham of the West. In less than two hours after reading the notice of the crime on the midnight express. Dyke Darrel was in Chicago. He visited the body of the murdered messenger, and made a brief examination. It was at once evident to Darrel, that Nicholson had made a desperate fight for life, but that he had been overpowered by a superior force. A reward of ten thousand dollars was already offered for the detection and punishment of the outlaws. "Poor Arnold!" murmured Dyke Darrel, as he gazed at the bruised and battered corpse. "I will not rest until the wicked demons who compassed this foul work meet with punishment!" There were still several shreds of hair between the fingers of the dead, when Dyke Darrel made his examination, since the body had just arrived from the scene of the murder. The detective secured several of the hairs, believing they might help him in his future movements. Darrel made one discovery that he did not care to communicate to others; it was a secret that he hoped might lead to results in the future. What the discovery was, will be disclosed in the progress of our story.