Gaston Sauverand walked off quietly between the deputy chief and Mazeroux.  He turned round in the doorway.

“Monsieur le Prefet, as you are making a search, I entreat you to take care of the papers on the table in my bedroom.  They are notes that have cost me a great deal of labour in the small hours of the night.  Also—­”

He hesitated, obviously embarrassed.

“Well?”

“Well, Monsieur le Prefet, I must tell you—­something—­”

He was looking for his words and seemed to fear the consequences of them at the same time that he uttered them.  But he suddenly made up his mind.

“Monsieur le Prefet, there is in this house—­somewhere—­a packet of letters which I value more than my life.  It is possible that those letters, if misinterpreted, will furnish a weapon against me; but no matter.  The great thing is that they should be safe.  You will see.  They include documents of extreme importance.  I entrust them to your keeping—­to yours alone, Monsieur le Prefet.”

“Where are they?”

“The hiding-place is easily found.  All you have to do is to go to the garret above my bedroom and press on a nail to the right of the window.  It is an apparently useless nail, but it controls a hiding-place outside, under the slates of the roof, along the gutter.”

He moved away between the two men.  The Prefect called them back.

“One second.  Mazeroux, go up to the garret and bring me the letters.”

Mazeroux went out and returned in a few minutes.  He had been unable to work the spring.

The Prefect ordered Chief Inspector Ancenis to go up with Mazeroux and to take the prisoner, who would show them how to open the hiding-place.  He himself remained in the room with Weber, awaiting the result of the search, and began to read the titles of the volumes piled upon the table.

They were scientific books, among which he noticed works on chemistry:  “Organic Chemistry” and “Chemistry Considered in Its Relations with Electricity.”  They were all covered with notes in the margins.  He was turning over the pages of one of them, when he seemed to hear shouts.

The Prefect rushed to the door, but had not crossed the threshold when a pistol shot echoed down the staircase and there was a yell of pain.

Immediately after came two more shots, accompanied by cries, the sound of a struggle, and yet another shot.

Tearing upstairs, four steps at a time, with an agility not to be expected from a man of his build, the Prefect of Police, followed by the deputy chief, covered the second flight and came to a third, which was narrower and steeper.  When he reached the bend, a man’s body, staggering above him, fell into his arms:  it was Mazeroux, wounded.

On the stairs lay another body, lifeless, that of Chief Inspector Ancenis.

Above them, in the frame of a small doorway, stood Gaston Sauverand, with a savage look on his face and his arm outstretched.  He fired a fifth shot at random.  Then, seeing the Prefect of Police, he took deliberate aim.