Chick saw nothing to be gained by further inquiries. He accepted the slender, shapely hand of the young woman, tendered while she was speaking, noting that there were tears in the sad and somber eyes with which she regarded him, forcing a faint, momentary smile to her finely curved lips. Gerald Vaughn, too, was equally impressive. There was something about both that lifted them above the ordinary, those indefinable qualities which denote class and character, and which alone serve to avert distrust and suspicion. Chick bowed and said a word of apology for having intruded, then accompanied Gerald Vaughn from the house. Nick Carter was in the meantime proceeding with the investigations in the Strickland apartment, but only with negative results. Adjoining the two front rooms was a third, partly furnished for a dining room and connecting with a spacious library. Back of these were two bedrooms, a bathroom, and a small kitchen, evidently but little used. A window in the kitchen and in one of the bedrooms, also a small ground-glass window in the bathroom, overlooked the area back of the house. Nick found that the first two were closed and securely locked, but that in the bathroom was open a few inches for ventilation. It was only about two feet square, and Nick looked in vain for any evidence denoting that a person had entered through it. Gazing out, he could see the gloomy area below, also the dark wall of the Carroll Building some twenty feet away, much too far for access to have been gained from any of its windows, all of which were those of business offices of one kind or another. Looking up, all that could be seen were the gloomy walls of the several buildings and a portion of the star-studded sky. “By Jove, the rascals have cleverly covered their tracks,” Nick muttered a bit grimly after these futile observations. “It was the work of no ordinary crooks. I should need daylight, I reckon, in order to pick up a thread worth following.” He was laboring at some disadvantage by means of the incandescent lamps only, and he returned in a few minutes to the front parlor. “Are those back windows as you found them, Arthur, when you returned with Mr. Strickland?” he inquired, when Gordon started up to meet him. “Yes, precisely,” he replied. “What have you learned?” “Very little thus far,” said Nick. “I see that the bathroom window is open a few inches, Mr. Strickland. Are you in the habit of leaving it open?” “Yes, Mr. Carter, I am,” was the reply. “But the bathroom door is always locked. The window, moreover, is hardly large enough to admit a man, nor could it be easily reached from the outside. I don’t see how the thieves could possibly have entered it.” “Crooks devise means which no honest man would think of,” Nick replied. “It is my opinion that----”