“Good Heavens! By whom, then, was it used?”
“Why—by Mademoiselle Stangerson.”
“I don’t understand,—or rather, I have never understood,” I said.
Rouletabille shrugged his shoulders.
“Is there nothing in this article in the ‘Matin’ by which you were particularly struck?”
“Nothing,—I have found the whole of the story it tells equally strange.”
“Well, but—the locked door—with the key on the inside?”
“That ’s the only perfectly natural thing in the whole article.”
“Really!—And the bolt?”
“The bolt?”