The hearth and the whole fireplace were tiled, and in the floor tiling, under the andirons, was a rectangular iron plate with an oval opening closed by an iron cover. This cover was hinged, and could be raised and thrown back to permit ashes to be swept into the chute. The iron plate was sunk flush with the hearth and cemented into the brickwork, and the cover fitted into the rim so closely that scarce a seam showed.

“He came up through this hole in the fireplace,” said Stone, almost as if talking to himself, “very soon after Miss Dupuy went upstairs at half-past ten. Before Mr. Carleton arrived at quarter after eleven, the murderer had finished his work, and had departed by this same means.”

While the others stood seemingly struck dumb by this revelation, Kitty excitedly flew to the fireplace and tried to raise the iron lid, but the andirons were in the way. Rob set them aside for her, while Stone said quietly, “Those andirons were probably not there that night?”