“True,” I said, rather crest-fallen.
“No,” continued Poirot, “we must look elsewhere for a solution of the open door mystery. One thing I am fairly sure of—they did not leave through the door. They left by the window.”
“What?”
“Precisely.”
“But there were no footmarks in the flower bed underneath.”
“No—and there ought to have been. Listen, Hastings. The gardener, Auguste, as you heard him say, planted both those beds the preceding afternoon. In the one there are plentiful impressions of his big hobnailed boots—in the other, none! You see? Some one had passed that way, some one who, to obliterate their footprints, smoothed over the surface of the bed with a rake.”
“Where did they get a rake?”
“Where they got the spade and the gardening gloves,” said Poirot impatiently. “There is no difficulty about that.”
“What makes you think that they left that way, though? Surely it is more probable that they entered by the window, and left by the door.”
“That is possible of course. Yet I have a strong idea that they left by the window.”