“The same one, Patsy,” replied Chick. “Then it is the Brown Robin.” “Perhaps. We’ll pipe off the house for a while.” The lineman came back to them, and learning what they were about to do, concluded to go off, but Chick persuaded him to stay. While he had every reason to believe that the young fellow was honest, yet he would not take the chance of having him give warning. The wait was half an hour in length, during which time the three were completely concealed under the areaway of a vacant house. About the time that Patsy expressed the opinion that the woman was settled for the night, a form was seen to appear on the stoop from within the house they were watching. “Here she comes!” cried Patsy. The figure descended the steps. “It’s a man,” said the lineman, “not a woman.” The figure turned from the house toward the west, approaching closely to the spot where the three were hidden. As the man passed them, the light of a street lamp fell upon him. Patsy caught the arm of Chick in a firm grip, and held it until the figure of the man passed far enough along to be beyond the possibility of hearing. “It is the one I followed this morning,” he whispered. “The deuce!” exclaimed Chick. “The one who wrote the letter—who went to sleep in the hotel?” “Yes; in the disguise he put on after he ran away from the insurance building.” “Get out and watch him,” said Chick to the lineman. The young fellow did as he was told, and presently reported that the man was crossing Irving Place and going up Seventeenth Street to the west. “Patsy,” said Chick, “go and rig yourself for the night’s work. I’ll take up the shadow and will give you the trail.” Patsy was about to go off, but he waited to hear Chick say to the lineman: “It isn’t worth your while to follow us longer.” But at the moment the lineman said: “The fellow is coming back.” Again the three went into hiding to see that the young fellow stopped at the corner of Irving Place. He stood there a moment or two, looking down the street, and passed out of sight. Patsy stole up to the corner, and lightly leaping into the courtyard of the house on the corner, threw himself on the ground and wriggled to the corner, to see the man standing nearby, leaning against the fence. Patsy wriggled back, and signaled to Chick that the man was there yet. Chick gave the return signal to keep up the watch, and himself stole down the street to the house whence the man had come. Looking up at it, there were no indications that it was occupied. Pulling from his pocket a false mustache and a wig, he donned them quickly, keenly alive to any signal Patsy might give, and, mounting the steps, rang the bell. Chick had a notion in his head that he wanted to satisfy. There was no response, though he rang several times. Then he tried the outer door. It opened to him, and he found himself in a vestibule. The inner doors were locked.