"The presence of another person in the room." "Somebody who escaped through the window!" exclaimed Caldew, placing his own interpretation on the deduction. "Do you suspect anybody?" "Not exactly. But I intend to investigate Captain Nepcote's actions on the night of the murder." Caldew, who lacked some of the information possessed by his companion, found this jump too great for his mind to follow. "For what purpose?" he asked. "Nepcote returned to France before the murder was committed." "He did not. He stayed in London that night, and did not return to France until the following day. He explained that yesterday by stating that when he reached London after leaving the moat-house he found another telegram from the War Office extending his leave for twenty-four hours." "Merrington said nothing of this to me. All he told me was that you and he had seen Nepcote, who identified the revolver as his property, and said that he had left it behind at the moat-house by accident." "Merrington is a man of fixed ideas, to use your phrase. He insisted on trying to fit in the loss of the necklace with his own theory of Hazel Rath's guilt. It was his obstinacy which led him to commit the folly of going to see Captain Nepcote before endeavouring to trace the missing necklace. It is only fair to Nepcote to add that he volunteered the information that he did not return to France on the night of the murder." "That does not seem like the action of a man with anything to hide," commented Caldew thoughtfully. "Unless he was facing a dangerous situation. In that case, frankness would be his best course to remove Merrington's suspicions. The fact that the murder was committed with his revolver is in itself a suspicious circumstance, in spite of the apparently plausible explanation. I have realized that all along. I had also previously acquainted Merrington with the fact that Nepcote did not return to France on the night of the murder, as was supposed. Merrington led up to that point skilfully enough, but it struck me that Nepcote saw the trap, and took the boldest course. It gave him time, at all events." "Time for what?" "Time to profit by Merrington's folly in putting him on his guard. Time to permit him to make his escape, if he is actually implicated in the crime." "Surely you are reading too much into this," exclaimed Caldew in a protesting voice. "Nepcote's story seems to me quite consistent with what we know of his movements. Miss Heredith, when giving us the names of the guests who had been staying at the moat-house, mentioned that Captain Nepcote had been recalled to France on the afternoon of the murder by a telegram from the War Office. Nepcote tells you that when he reached London he found another telegram awaiting him extending his leave. Surely that is consistent?"