There was a loud burst of laughter. It was the chief of the detective-service indulging his merriment:
"Lupin! Always Lupin! Lupin is in everything; Lupin is everywhere!"
"He is just where he is," said Ganimard, angrily.
"And then he must have his reasons for being in any particular place," remarked M. Dudouis, "and, in this case, his reasons seem to me obscure. The writing-desk has not been broken open nor the pocketbook stolen. There is even gold left lying on the table."
"Yes," cried Ganimard, "but what about the famous diamond?"
"What diamond?"
"The blue diamond! The celebrated diamond which formed part of the royal crown of France and which was presented by the Duc d'Alais to Léonide Latouche and, on her death, was bought by Baron d'Hautrec in memory of the brilliant actress whom he had passionately loved. This is one of those recollections which an old Parisian like myself never forgets."
"It is obvious," said the examining magistrate, "that, if the blue diamond is not found, the thing explains itself. But where are we to look?"
"On monsieur le baron's finger," replied Charles. "The blue diamond was never off his left hand."