“Clameran,” he continued, “Clameran alone has Mme. Fauvel in his power.  Now, the question is, what is the secret of this terrible influence he has gained over her?  I have positive proof that they have not met since their early youth until fifteen months ago; and, as Mme. Fauvel’s reputation has always been above the reach of slander, we must seek in the past for the cause of her resigned obedience to his will.”

“We can never discover it,” said Prosper mournfully.

“We can discover it as soon as we know Clameran’s past life.  Ah, to-night he turned as white as a sheet when I mentioned his brother Gaston’s name.  And then I remembered that Gaston died suddenly, while his brother Louis was making a visit.”

“Do you think he was murdered?”

“I think the men who tried to assassinate me would do anything.  The robbery, my friend, has now become a secondary detail.  It is quite easily explained, and, if that were all to be accounted for, I would say to you, My task is done, let us go ask the judge of instruction for a warrant of arrest.”

Prosper started up with sparkling eyes.

“Ah, you know—­is it possible?”

“Yes, I know who gave the key, and I know who told the secret word.”

“The key might have been M. Fauvel’s.  But the word——­”

“The word you were foolish enough to give.  You have forgotten, I suppose.  But fortunately Gypsy remembered.  You know that, two days before the robbery, you took Lagors and two other friends to sup with Mme. Gypsy?  Nina was sad, and reproached you for not being more devoted to her.”

“Yes, I remember that.”

“But do you remember what you replied to her?”

“No, I do not,” said Prosper after thinking a moment.

“Well, I will tell you:  ’Nina, you are unjust in reproaching me with not thinking constantly of you; for at this very moment your dear name guards M. Fauvel’s safe.’”

The truth suddenly burst upon Prosper like a thunderclap.  He wrung his hands despairingly, and cried: 

“Yes, oh, yes!  I remember now.”

“Then you can easily understand the rest.  One of the scoundrels went to Mme. Fauvel, and compelled her to give up her husband’s key; then, at a venture, placed the movable buttons on the name of Gypsy, opened the safe, and took the three hundred and fifty thousand francs.  And Mme. Fauvel must have been terribly frightened before she yielded.  The day after the robbery the poor woman was near dying; and it was she who at the greatest risk sent you the ten thousand francs.”

“But which was the thief, Raoul or Clameran?  What enables them to thus tyrannize over Mme. Fauvel?  And how does Madeleine come to be mixed up in the affair?”

“These questions, my dear Prosper, I cannot yet answer; therefore I postpone seeing the judge.  I only ask you to wait ten days; and, if I cannot in that time discover the solution of this mystery, I will return and go with you to report to M. Patrigent all that we know.”