We strode through the empty room, awakening dismal echoes as we trod the bare boards, and flung open the other door. At top and bottom, similar groups of screw-holes showed that this also had been made secure, and that these bolts had been of the same very substantial character as the others.

Thorndyke turned away from the door with a slight frown.

“If we had any doubts,” said he, “as to what has been going on in this house, these traces of massive fastenings would be almost enough to settle them.”

“They might have been there before Weiss came,” I suggested. “He only came about seven months ago and there is no date on the screw-holes.”