“Are you sure the door was closed and locked when you went out?” “Yes, absolutely.” “Who occupies the floor below?” “Madame Denise, a fashionable milliner. Her rooms were open when we returned. Several girls were busy in the workroom. Madame Denise was in her display room in the front of the house. The door has a large plate-glass panel and is within a few feet of the street door.” “You have questioned her, I infer?” Nick put in. “Yes, certainly. I went down and questioned her after telephoning to you. She had only a few customers this evening, but was in the front room all the while. She is positive that no persons have visited these rooms, or left them, by means of the stairs and the street door. Such a quantity of plunder could not possibly have been taken out that way without her observing it.” “Is there a rear door from the house?” Nick inquired. “Yes,” Gordon quickly nodded. “It leads to a small paved area between the back of this and the adjoining dwelling and the side wall of the Carroll Building. I have learned positively, however, that no persons have been in or out of the rear door.” “From whom?” “From the janitor. He is thoroughly trustworthy. He lives in a rear room on the ground floor. He has been there all of the evening, and the door of his room has not been closed. No person could have passed through the hall without his having seen or heard him. He is absolutely sure there have been no intruders.” “By Jove, it does appear a bit mysterious,” Chick remarked. “Plainly enough the plunder must have been taken out in some direction,” Nick replied. “Who occupies the upper floor of the house?” “Victor Gilbert, the well-known photographer. He is the only tenant on that floor. His integrity is beyond question.” “Very true,” Nick allowed. “I know him personally.” “His rooms were closed at six o’clock and have not since been occupied, so far as I can learn,” Gordon went on. “I have telephoned to him, telling him of the robbery, and he now is on his way here, that we may visit his rooms. It does not seem possible, however, that the robbery can have been committed from above.” “Nor from below, Arthur, if all you have stated is correct,” Nick said, a bit dryly. “Is it possible to reach the back windows of this apartment from those of the Carroll Building?” “No, no; it is quite impossible,” Gordon protested. “The distance is more than twenty feet. Besides, Nick, there is no evidence that the windows of this flat have been opened. All of them were securely locked and----” “I will inspect them presently,” Nick interrupted. “It is very evident, at least, that robbers have been here, and I know their knavery was not accomplished by any supernatural means. Who knew of Mr. Strickland’s intention to dine with you and be absent from his apartments this evening?”