The police officers of Rouen, convinced of their own impotence, solicited the assistance of the Parisian detective force. Mon. Dudouis, chief of the Sûreté, sent the best sleuths of the iron brigade. He himself spent forty-eight hours at the castle, but met with no success. Then he sent for Ganimard, whose past services had proved so useful when all else failed.
Ganimard listened, in silence, to the instructions of his superior; then, shaking his head, he said:
“In my opinion, it is useless to ransack the castle. The solution of the problem lies elsewhere.”
“Where, then?”
“With Arsène Lupin.”
“With Arsène Lupin! To support that theory, we must admit his intervention.”
“I do admit it. In fact, I consider it quite certain.”
“Come, Ganimard, that is absurd. Arsène Lupin is in prison.”
“I grant you that Arsène Lupin is in prison, closely guarded; but he must have fetters on his feet, manacles on his wrists, and gag in his mouth before I change my opinion.”
“Why so obstinate, Ganimard?”