"What a man!" muttered Coquenil.
"We know the facts," went on Hauteville sternly, "we know why you killed Martinez and why you disguised yourself as a wood carver."
The prisoner's face lighted with a mocking smile. "If you know all that, why waste time questioning me?"
"You're a good actor, sir, but we shall strip off your mask and quiet your impudence. Look at the girl in this false picture which you had cunningly made in Brussels. Look at her! Who is she? There is the key to the mystery! There is the reason for your killing Martinez! He knew the truth about this girl."
Now the prisoner's pulse was running wild, faster and faster, but with no more violent spurtings and leapings; the red column throbbed swiftly and faintly at the bottom of the tube as if the heart were weakening.
"A hundred and sixty to the minute," whispered Duprat to the magistrate. "It is dangerous to go on."
Hauteville shrugged his shoulders.
"Martinez knew the truth," he went on, "Martinez held your secret. How had Martinez come upon it? Who was Martinez? A billiard player, a shallow fellow, vain of his conquests over silly women. The last man in Paris, one would say, to interfere with your high purposes or penetrate the barriers of wealth and power that surrounded you."
"You—you flatter me! What am I, pray, a marquis or a duke?" chaffed the other, but the trembling dial belied his gayety, and even from the side Coquenil could see that the man's face was as tense and pallid as the sheet before him.
"As I said, the key to this murder," pursued the magistrate, "is the secret that Martinez held. Without that nothing can be understood and no justice can be done. The whole aim of this investigation has been to get the secret and we have got it! Groener, you have delivered yourself into our hands, you have written this secret for us in words of terror and we have read them, we know what Martinez knew when you took his life, we know the story of the medal that he wore on his breast. Do you know the story?"