"Well, the principle involved in that story explains the presence of the rings in the midst of this stack of letters. Franklin Van Burnam, if he is the murderer of his sister-in-law, is one of the subtlest villains this city has ever produced, and knowing that, if once suspected, every secret drawer and professed hiding-place within his reach would be searched, he put these dangerous evidences of his guilt in a place so conspicuous, and yet so little likely to attract attention, that even so old a hand as myself did not think of looking for them there." He had finished, and the look he gave me was for myself alone. "And now, madam," said he, "that I have stated the facts of the case against Franklin Van Burnam, has not the moment come for you to show your appreciation of my good nature by a corresponding show of confidence on your part?" I answered with a distinct negative. "There is too much that is unexplained as yet in your case against Franklin," I objected. "You have shown that he had motive for the murder and that he was connected more or less intimately with the crime we are considering, but you have by no means explained all the phenomena accompanying this tragedy. How, for instance, do you account for Mrs. Van Burnam's whim in changing her clothing, if her brother-in-law, instead of her husband, was her companion at the Hotel D----?" You see I was determined to know the whole story before introducing Miss Oliver's name into this complication. He who had seen through the devices of so many women in his day did not see through mine, perhaps because he took a certain professional pleasure in making his views on this subject clear to the attentive Inspector. At all events, this is the way he responded to my half-curious, half-ironical question: "A crime planned and perpetrated for the purpose I have just mentioned, Miss Butterworth, could not have been a simple one under any circumstances. But conceived as this one was by a man of more than ordinary intelligence, and carried out with a skill and precaution little short of marvellous, the features which it presents are of such a varying and subtle character that only by the exercise of a certain amount of imagination can they be understood at all. Such an imagination I possess, but how can I be sure that you do?" "By testing it," I suggested. "Very good, madam, I will. Not from actual knowledge, then, but from a certain insight I have acquired in my long dealing with such matters, I have come to the conclusion that Franklin Van Burnam did not in the beginning plan to kill this woman in his father's house.