"Furthermore, I can think of no way by which Argot could have run across Brown. He would naturally follow the man whom he believed to be his wife's lover, and not only did Madame Argot tell you that her husband ran out the back way in pursuit of her cousin, but that seems to me the thing which he would most likely do. And yet, having left by that door, he could not possibly have got into the house again unperceived. Therefore, I cannot imagine how he could have met Allan Brown. No, there is really not a scrap of real evidence against the Frenchman. Now, there remains Miss Derwent. She could easily have obtained the key; she could also have hidden the body. But there is absolutely nothing to connect her with the murder, or the victim--nothing. And yet, Doctor, I have always believed that she knew more about this crime than she was willing to acknowledge, and I may as well tell you now that the reason I took such pains to inform Miss Derwent of Mrs. Atkins's plight, was that I thought that, rather than allow an innocent person to suffer, she would reveal the name of the true author of the crime. You see, I had exhausted every means of discovering her secret, without the least result. My only hope of doing so now lay with her. But my ruse failed. She has given no sign, although, for aught she knows, Mrs. Atkins may be languishing in a prison, or is being hunted from house to house or from city to city. I am therefore forced to believe that Miss Derwent's mysterious secret has absolutely nothing to do with the Rosemere murder." "I have always been sure of it." "But the fact remains that the man was killed. And yet every person who could by any possibility have committed the crime has practically been proved guiltless. I'm getting old." And he sighed deeply. "So you have given the case up!" "No, sirree. But I confess I'm not very hopeful. If I failed to pick up a clue while the scent was fresh, there ain't much chance of my doing it now. So I guess you've won your bet, Doctor," he went on, as he pulled a roll of bills out of his pocket. "Certainly not. I bet that a man committed the crime, and that has not been proved, either." "That's so! Well, good-day, Doctor. Hope I'll see you again. I tell you what, you should have been on the force." And so we parted. He had hardly shut the door behind him, when my boy came in with a note. The handwriting was unknown to me. I tore the envelope open, and threw it down beside me. This is what I read: DEAR DR. FORTESCUE, I am in great trouble and beg you to come to me as soon as you possibly can. Sincerely yours, MAY DERWENT. "Any answer, sir?" "No." I should be there as soon as the messenger.