Just as I was about to turn away from the desk, my eyes fell upon a piece of paper which was peering out from under the typewritten manuscript. I pulled it forth to see what it might be. It was part of a typewritten letter dated the day before, but with no address or signature. There could not have been a signature, for the lower half of the letter was missing. The sheet was torn across as if some one had wished to destroy the signature. It read: “Tuesday. “Mr. Henry Warren, “My dear Professor, “I will call upon you to-morrow around five o'clock. I feel sure you can spare me a few moments. If I can only make you see how great a thing you can do for humanity, I am sure you will take my viewpoint. The consequences of the step you are taking are so momentous that unless—” And there the letter ended, for the rest of the sheet had been torn off. It was a curious sort of a letter, and seemed to contain a warning of some sort. It was written upon a typewriter whose ribbon was far from clean. Not only did it contain a warning, but it seemed to me there was a threat in the words. But more important than anything else was the statement that the writer would call upon Warren. As it had been written the day before, Warren must have seen the person only an hour before he died. Without a word I handed the letter to Ranville and watched his face as he read. When he came to the end, I saw his eyebrows raise a little, and he turned to me. “This looks important, Pelt. Any signs of the missing portion of the sheet?” I shook my head, and we both turned to the desk. We went through every paper, lifting them from each other, and even turning the pages of the books. But we found nothing. Then we turned our attention to the wastebasket, turning the contents upon a small rug. But the basket contained only the discarded notes which had been thrown aside and a few matches. The missing half of the letter we did not find. As we paused, I noticed that the chief and Carter were before the bookcase—the bookcase with the broken glass. Ranville placed the letter in his pocket and said: “What do you make of it?” I told him what I thought, that it contained both a warning and a threat, and then said that it looked as if the missing part had been taken in order to destroy the signature. “True enough,” came the drawling answer. “But why did they not take the entire letter? Why destroy half of it and leave the other? If the whole note had been taken we would never have known anything about it. To take but half seems a very illogical thing to do.” Hearing our voices, Carter and the chief came to the desk and asked what we had found. Ranville handed him the letter, and after they had both looked at it the chief held it a long while in his hand. His face was a study, and he slowly shook his head. He might have spoken if Carter had not said: