“Nobody knew it, Mr. Carter,” Miss Strickland cried, with girlish earnestness. “We did not know it ourselves until after we came here. We then persuaded Uncle Rudolph to go with us.” “Were any other persons present?” “No, sir, only we three. No one could have overheard us.” “Mina is right,” put in Gordon. “No person could have known that Mr. Strickland would be absent this evening. It was entirely unpremeditated. The crime could not have been planned from any knowledge of our intention.” “Do you keep any servants, Mr. Strickland?” Nick inquired, turning to him. He had overcome his agitation, his terrible distress immediately following his discovery of the crime, made hardly an hour before. He appeared to derive much hope and encouragement from what Nick had said to him, and from the fact that an investigation by the famous detective already was in progress. Arthur Gordon had, in fact, telephoned immediately to Nick for assistance after making the superficial investigation mentioned, and finding the robbery so shrouded in mystery as, he felt sure, to completely baffle the ordinary police. It was about ten o’clock when the two detectives arrived upon the scene. “No, I keep no servants,” said Mr. Strickland, replying to Nick’s question. “As you may infer, Mr. Carter, I have always been very careful to protect my treasures. My lost Stradivarius alone is worth forty thousand dollars. I would not have parted with it for ten times that sum. The door of my apartments is a very strong one, and it is provided with two heavy locks, which act automatically. My windows have patent fastenings, and they are always closed and securely locked when I am absent. This evening was no exception.” “But who takes care of your rooms?” Nick inquired. “Do you look after them yourself?” “Oh, no, not the care and cleaning of them,” said Mr. Strickland. “I employ a woman from the adjoining house, that occupied by Mr. Gerald Vaughn and his sister, both of whom are friends of mine. I pay their housekeeper, Mrs. Amelia West, to come in each day to make my bed and put my sleeping room in order, and to come once a week to sweep and dust all of my rooms.” “I see,” Nick remarked, with a nod. “She has been doing so for nearly three months,” Mr. Strickland added. “Alas! I now must find another. I am more than sorry to lose her.” “What is the trouble?” Nick questioned. “Has she been discharged by Mr. Vaughn?” “Oh, no!” Mr. Strickland shook his head sadly. “Mrs. West died quite suddenly yesterday morning.” CHAPTER II. A VAIN SEARCH. Nick Carter ended his interrogations quite abruptly. “I will look around for myself in search of evidence,” he remarked, turning to Arthur Gordon. “You had better remain here with Mr. Strickland and his niece. If I require anything, or wish to add to my inquiries, I will call you. I shall return in a few minutes.” “Go ahead,” Gordon nodded. “The case is in your hands.”