impossible to form any idea as to how the murderer got out of The Yellow Room, or how he got across the laboratory to reach the vestibule! Ah, yes, Monsieur Rouletabille, it is altogether as you said, a fine case, the key to which will not be discovered for a long time, I hope."
"You hope, Monsieur?"
Monsieur de Marquet corrected himself.
"I do not hope so,—I think so."
"Could that window have been closed and refastened after the flight of the assassin?" asked Rouletabille.
"That is what occurred to me for a moment; but it would imply an accomplice or accomplices,—and I don't see—"
After a short silence he added:—
"Ah—if Mademoiselle Stangerson were only well enough to-day to be questioned!"
Rouletabille following up his thought, asked:—
"And the attic?—There must be some opening to that?"
"Yes; there is a window, or rather skylight, in it, which, as it looks out towards the country, Monsieur Stangerson has had barred, like the rest of the windows. These bars, as in the other windows, have remained intact, and the blinds, which naturally open inwards, have not been unfastened. For the rest, we have not discovered anything to lead us to suspect that the murderer had passed through the attic."
"It seems clear to you, then, Monsieur, that the murderer escaped—nobody knows how—by the window in the vestibule?"
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