Some time longer the detective and official talked, and the lamps in the streets were lit when Dyke Darrel left the presence of Mr. Holden, and turned his steps toward a hotel. "I must send a line to Nell," mused the detective, as he moved along. "I shall remain a short time in St. Louis, as I may pick up some points here that will be of use to me. I am of the opinion that either this city or Chicago holds the perpetrators of this latest railroad crime." The detective did not see the shadowy form flitting along not far behind. A man had shadowed the detective since his departure from the railway office. Dyke Darrel, in order to make a short cut, had entered a narrow street, where the lights were few and the buildings dingy and of a mean order. Moving on, deeply wrapped in thought, the detective permitted his "shadow" to steal upon him, and just as Dyke Darrel came opposite a narrow alley, the shadow sprang forward and dealt him a stunning blow on the head. The detective reeled, but did not fall. Partially stunned, he turned upon his assailant, only to meet the gleam of cold steel as a knife descended into his bosom! CHAPTER VII. WHAT A HANDKERCHIEF REVEALED. Dyke Darrel was so dazed from the blow he had received as to be unable to ward off the dirk that was thrust at his bosom by the vile assassin, and had not a third party appeared on the scene at this critical moment the story we are now writing would never have been told. A kind Providence had on more than one occasion favored the daring railroad detective. Before the point of the knife touched the breast of Dyke Darrel, a swift-flying object sent the deadly weapon out into the middle of the street. The next instant a man bounded from the shadow of a building upon the would-be assassin. There was a short struggle, when the last comer found, that instead of the detective's assailant, he held a coat in his hands. The villain had made good his escape. "Confound you!" greeted the new comer. "Who was it?" "I saw him following you, sir, and made up my mind that some villainy was in the wind. I do not know who the villain was. Are you hurt?" "Not in the least." Then the two men walked on until a lamp-post was gained. Here the features of each were plainly revealed. A low exclamation fell from the lips of Dyke Darrel. "Good thunder, Harry Bernard! how are you? Where in the world did you spring from?" The detective grasped and wrung the man's hand warmly--a rather slender young fellow, with brown hair and eyes, a mustache being the only sign of beard on his face. "One question at a time, Dyke," returned the young man with a laugh. "I mistrusted it was you all the time. It strikes me that you are becoming careless in your old age. Hope you're not in love--THAT makes a fool of a man sometimes?" "Does it? No, I'm not in any such predicament; fact is, I am wedded to my profession and shall never marry. But, Harry, you haven't answered my questions yet."