This was the commencement of the case. Who the stout man was Taggart could not surmise. It might be one of a score of thieves, and for four days he could form no conception of the murderer's identity, until one night, waking from a restless slumber, Huey Donnelly flashed like thought across his mind, and running his memory back for the past few weeks, he remembered that at the time the murder was committed Donnelly was in the city. The great difficulty in tracing the case was passed. Donnelly was at once watched. Who the second man was Taggart well surmised. He followed Huey to every quarter of the city to see if he communicated with his pal, who was with him when the chisel was purchased--who was with him when the porter was murdered. But the second murderer had fled. Taggart himself followed Donnelly night after night, dogged him into every rum-mill and thieves' brothel, where he tarried briefly or long, watching him at night until he went to bed, but never found his pal, who is the associate criminal in the tragedy. A week after Donnelly was spotted, Taggart found his pal had left the city, and unless Donnelly was arrested he would also leave. Following up the trail, he met Huey in Washington Square. Donnelly was leisurely crossing when a hand was laid heavily on his shoulder. He turned and faced the detective, who simply said: 'I want you, Donnelly.' 'What for?' 'Murder.' "When at the station, the salesman was sent for. Donnelly's black moustache was gone. His face was shaved clean. He was placed in the rogue's gallery. A number of men of similar build, both moustached and clean face, were placed in the same room. The salesman was conducted to the gallery. 'Point out the man who purchased the chisel,' was the detective's command. Without hesitation or doubt, the salesman placed his hand on Donnelly's shoulder. Then Taggart followed the second murderer. He went to Baltimore, but he could get no further. All clue was lost in that city, and the present lurking place of the confederate of Donnelly is undiscovered. The necessity for keeping the arrest quiet was removed, and now the detective calls to his aid the far reaching influence of the press and the telegraph, that police authorities of other cities may complete the work begun here, and render to justice the other murderer, who is at liberty in spite of her laws." It would require a volume to narrate all of the exploits of the detectives, and so we shall content ourselves with the incidents already given. If, as we have said, persons seeking the aid of the police, would tell the truth in their statements, the aid rendered them would be much more efficacious and speedy; and, after all, it is useless to try to deceive these keen students of human nature. The detective can tell from the nature of the loss whether the statement of the circumstances is true or false, for he knows that certain robberies take place only in certain localities.