“Well, it seems very logical to say that if the person who wrote it had not wished any one to see it, he or she would have destroyed the entire letter. To simply tear off the signature—if there was one—meant nothing. If they wished to have no one see the letter they would have destroyed it all. Then, it is written on this typewriter. The secretary says that no one was in the library during the time she was here on that last day. I do not think she wrote it; the murderer might have done so, and if so, he wrote it to make you think just what you did think.” As the chief's eyes expressed his wonder, Bartley added: “Suppose, for instance, that the person who killed Warren did it in a sudden fit of frenzy. Then, when the deed was over, there came the second cooler thought—he had committed a murder. Criminals, that is, all that I know, always make mistakes. This one realized he was pretty safe, but he thought he had better make it safer, throw suspicion on some one else. Seeing the typewriter, he wrote that part of the letter you see, and left it where he knew some one would find it. And by doing that he defeated the very thing he wanted us to think. For if he had not left that portion, we would not have known anything about it. It is a very mysterious murder at the best, and this makes it more so.” “You're right when you say it is a mysterious murder,” shot forth the chief. “It's damned mysterious. And here am I—without any clews, without any sort of a chance to solve it. There is nothing missing even from the room.” “Oh, yes, there is,” came Bartley's quick comment. “There is not,” answered the chief. “That girl knows the room, everything in it. She says there is nothing missing.” “But then she is mistaken,” was the cool reply. As the chief started to speak, he went on: “The girl told you the truth, and yet she is mistaken. There is something missing. It is the rest of that edition of De Sade,” and he pointed to the red-covered book which he placed on the surface of the desk. The chief's eyes went to the book, but he glanced at it as if he did not believe what Bartley had said. Then, as he turned, he burst out: “What do you mean?” “This, Chief. I happen to know about this edition of De Sade's ‘Justine.’ It is not very common, though it is very famous; perhaps I had better say ‘infamous.’ The original edition was in ten small volumes with one hundred illustrations—illustrations as bad as the text. The author, a pathological case, spent most of his time in insane asylums, sent there first by Napoleon. He was not insane, however, in the strict sense of the word. Now, as I said, there were ten volumes. The secretary said that the last eight volumes of the set Mr. Warren had were bound two to a book; the first two were not.” There was a perplexed look on the chief's face. He was trying to follow Bartley, but did not seem to understand just what it was all about. Seeing this, Bartley explained: