Robelot made a sign of protesting.

“Shut up now,” said M. Lecoq.  “And your cutlass?”

While this conversation was going on, M. Plantat reflected.

“Perhaps,” he murmured, “I’ve spoken too soon.”

“Why so?” asked M. Lecoq.  “I wanted a palpable proof for Monsieur Domini; we’ll give him this rascal, and if he isn’t satisfied, he’s difficult to please.”

“But what shall we do with him?”

“Shut him up somewhere in the house; if necessary, I’ll tie him up.”

“Here’s a dark closet.”

“Is it secure?”

“There are thick walls on three sides of it, and the fourth is closed with a double door; no openings, no windows, nothing.”

“Just the place.”

M. Plantat opened the closet, a black-looking hole, damp, narrow, and full of old books and papers.

“There,” said M. Lecoq to his prisoner, “in here you’ll be like a little king,” and he pushed him into the closet.  Robelot did not resist, but he asked for some water and a light.  They gave him a bottle of water and a glass.

“As for a light,” said M. Lecoq, “you may dispense with it.  You’ll be playing us some dirty trick.”

M. Plantat, having shut the closet-door, took the detective’s hand.

“Monsieur,” said he, earnestly, “you have probably just saved my life at the peril of your own; I will not thank you.  The day will come, I trust, when I may—­”

The detective interrupted him with a gesture.

“You know how I constantly expose myself,” said he, “once more or less does not matter much.  Besides, it does not always serve a man to save his life.”  He was pensive a moment, then added:  “You will thank me after awhile, when I have gained other titles to your gratitude.”

M. Gendron also cordially shook the detective’s hand, saying: 

“Permit me to express my admiration of you.  I had no idea what the resources of such a man as you were.  You got here this morning without information, without details, and by the mere scrutiny of the scene of the crime, by the sole force of reasoning, have found the criminal:  more, you have proved to us that the criminal could be no other than he whom you have named.”

M. Lecoq bowed modestly.  These praises evidently pleased him greatly.

“Still,” he answered, “I am not yet quite satisfied.  The guilt of the Count de Tremorel is of course abundantly clear to me.  But what motives urged him?  How was he led to this terrible impulse to kill his wife, and make it appear that he, too, had been murdered?”

“Might we not conclude,” remarked the doctor, “that, disgusted with Madame de Tremorel, he has got rid of her to rejoin another woman, adored by him to madness?”

M. Lecoq shook his head.

“People don’t kill their wives for the sole reason that they are tired of them and love others.  They quit their wives, live with the new loves—­that’s all.  That happens every day, and neither the law nor public opinion condemns such people with great severity.”