“The handwriting is not the same on the envelope and the box.  The writing on the envelope is less plain, a little shaky, obviously imitated.”

“Which proves—?”

“Which proves, Monsieur le Prefet, that this yellow envelope does not come from your detective.  I presume that, after writing his report at a table in the Cafe du Pont-Neuf and closing it, he had a moment of inattention during which somebody substituted for his envelope another with the same address, but containing a blank sheet of paper.”

“That’s a supposition!” said the Prefect.

“Perhaps; but what is certain, Monsieur le Prefet, is that your inspector’s presentiments are well-grounded, that he is being closely watched, that the discoveries about the Mornington inheritance which he has succeeded in making are interfering with criminal designs, and that he is in terrible danger.”

“Come, come!”

“He must be rescued, Monsieur le Prefet.  Ever since the commencement of this meeting I have felt persuaded that we are up against an attempt which has already begun.  I hope that it is not too late and that your inspector has not been the first victim.”

“My dear sir,” exclaimed the Prefect of Police, “you declare all this with a conviction which rouses my admiration, but which is not enough to establish the fact that your fears are justified.  Inspector Verot’s return will be the best proof.”

“Inspector Verot will not return.”

“But why not?”

“Because he has returned already.  The messenger saw him return.”

“The messenger was dreaming.  If you have no proof but that man’s evidence—­”

“I have another proof, Monsieur le Prefet, which Inspector Verot himself has left of his presence here:  these few, almost illegible letters which he scribbled on this memorandum pad, which your secretary did not see him write and which have just caught my eye.  Look at them.  Are they not a proof, a definite proof that he came back?”

The Prefect did not conceal his perturbation.  The others all seemed impressed.  The secretary’s return but increased their apprehensions:  nobody had seen Inspector Verot.

“Monsieur le Prefet,” said Don Luis, “I earnestly beg you to have the office messenger in.”

And, as soon as the messenger was there, he asked him, without even waiting for M. Desmalions to speak: 

“Are you sure that Inspector Verot entered this room a second time?”

“Absolutely sure.”

“And that he did not go out again?”

“Absolutely sure.”

“And your attention was not distracted for a moment?”

“Not for a moment.”

“There, Monsieur, you see!” cried the Prefect.  “If Inspector Verot were here, we should know it.”

“He is here, Monsieur le Prefet.”

“What!”

“Excuse my obstinacy, Monsieur le Prefet, but I say that, when some one enters a room and does not go out again, he is still in that room.”