"Who unlocked the library door when Doctor Marcy returned with my Cousin Betty?" "Marcy says it was Effingham. Miss Trevor would want to get the master-key out of her possession the instant that she had accomplished her purpose of replacing the despatch-box. And somehow she managed it, even though Betty and the doctor arrived on the scene a trifle in advance of Effingham's return with the ammonia." "Very well; we'll drop that issue for the present. Assuming that you have fairly reconstructed the action connected with the abstraction of the despatch-box and its return to the room, there still remains the question of how Francis Graeme came to his death. Was it the accident of his falling and striking his head on that same iron box, or was he attacked from behind? Remember that the postern-door was unlocked all the time." "I don't think it was Eunice Trevor who killed him," returned Warriner. "Of course, it is conceivable that she entered by the secret way, struck Graeme down, and escaped with the despatch-box; everything else following as before. But, in the first place, she is a woman, and below the normal feminine in the matter of physique. An assault of this nature is no child's play, even granting the element of complete surprise. Secondly, it is pretty clear that she entered the library in obedience to a signal from John Thaneford. He had been watching the progress of events through his wonderful telephoto lens, and the waving of a handkerchief told her that the way was open." "How about Thaneford himself?" "Assuming that it was a murder, I still see no ground for trying to fix the guilt on him. He could hardly have approached the library that morning without being seen by Zack and Zeb." "He might have had an accomplice, or rather a tool. But I suppose that hypothesis is open to the same objection--the continued presence of the two men who were mowing the lawn?" "Yes and no," returned Warriner thoughtfully. "A white man certainly would be noticed. But there are always negroes coming and going about our Southern houses, and Zeb and Zack would have paid no attention to anyone of their own color. Moreover, there are plenty of bad niggers capable of cutting your throat for a couple of dollars." "But think of the risk involved in using such an instrument!" I exclaimed. "And somehow I can't quite believe it of John Thaneford, heartily as I dislike him. I can understand his committing this alleged crime with his own hand, but I don't see him hiring a black thug to act for him." "Nor I," agreed Warriner. "It isn't in the picture." "And so we come back to the verdict of the coroner's jury: Dead by the visitation of God. Only it's curious----" "Yes?" "----that John Thaneford should have had such definite foreknowledge that the visitation in question was impending. Remember the look-out on Sugar Loaf and the handkerchief marked with his initials."