Both Jourdan and Kelso were agreed that this theory of the commission of the crime was correct, and this led to the inevitable conclusion that the murder was the work of an "outsider," that is, of some one not properly belonging to the criminal class. The weapon with which the murder had been committed was one which the Detectives had never before encountered in the annals of crime, and its appearance indicated long use in its legitimate sphere. No burglar or professional thief would have used it, and none of the inmates of the house recognized it as belonging to the mansion. Again, the professional thief would have despatched his victim with more speed and less brutality. There was not the slightest sign of the thief having forced an entrance into the mansion, and the most rigid search failed to reveal the mark of a burglar's tool on any of the doors or windows. This fact warranted the conclusion that the murderer had secreted himself in the house during the day. From the first Jourdan was convinced that the assassin was one of a class who pursue an honest trade during the day, and seek to fill their pockets more rapidly by committing robberies at night. From this conviction he never wavered. As he stood by the side of the murdered man, Jourdan recognized the difficulty of the task of finding the assassin. The "dog" bewildered him. Had the weapon been any kind of a burglar's tool, or anything that any description of thief had ever been known to use, he would have been able to trace it to some one in the city; but the facts of the case plainly indicated that the assassin was an "outsider," and even Jourdan and Kelso were at a loss to know how to proceed to find him.