After having interrogated all the witnesses of last night's tragedy he could get into touch with, JÉrÔme Fandor returned to the Palais de Justice.

"All the same," he confessed to himself, "I must admit that, up to the present, I do not know anything very definite about it. This Princess Sonia Danidoff has managed to get robbed in a most extraordinary way. At one o'clock in the morning, Havard declares that the thief can be none other than one of the guests, and thereupon every person present has to submit to being searched—an exhaustive search! Nothing comes of it. Then Bertillon arrives on the scene, and it seems he has obtained very distinct imprints of finger marks. If they are as distinct as all that, the task of the police will be simplified; but, on the other hand, is it likely the guilty person will be so simple as to respond to the summons issued by the Public Prosecutor, a general summons issued to all Thomery's guests to parade in Bertillon's office for the finger-mark test?... Not he! Why the moment he heard of it he would make for the train and pass the frontier!"

When his cab arrived at the Palais, Fandor uttered a big sigh of satisfaction:

"There are a good many things I am not clear about: let us hope Bertillon will give me some information."

The entrance to the anthropometric department was under the discreet observation of two detectives:

"Oh," thought Fandor. "They think it probable there will be an immediate arrest, do they? We are going to have some complications, I foresee, in connection with the finger-mark ceremony!"

He sent in his card and a few minutes after he found himself in the presence of Monsieur Bertillon.

"Well, what is it you want me to tell you?" asked this famous man of science.

"Why, dear master, everything that took place last night! Is it true that you have summoned here all Thomery's guests?... Have you obtained such perfect reprints that, in your hasty examination, you can be certain of identifying them with those of the persons who will pass through your office to undergo the test?"

Bertillon smiled:

"Oh, my dear fellow, you are of those who do not put much faith in the results of my tests for police purposes! That, let me tell you, is because you are not acquainted with our procedure. The impressions I obtained are distinct—precise as can be; if an arrest is made before long it will be made on sure grounds."

Fandor bowed:

"I accept your statement, dear master!... But, do be kind enough to tell me what happened after my departure?"

"Oh, nothing very extraordinary.... Of course you know about the affair—how the Princess Sonia Danidoff was discovered?..."

"What I know is that Thomery found one of his guests, Princess Sonia Danidoff, in a dead faint in a small drawing-room; that Dr. Du Marvier declared she had been rendered unconscious; that the theft of a pearl necklace worn by the victim had been the motive of this criminal attempt; that Monsieur Havard, called in at once, first made sure that no one had left the house, and then had everyone on the premises searched ... and that is really all I know about it!"

"Well, Havard did not find anything!"

"No one was caught with compromising jewels in their possession. The last guest gone, the house searched from top to bottom, not a single pearl had been found.... I arrived just when the investigations had terminated: at the moment when they were about to take the Princess home. She had regained consciousness by this time and declared she knew nothing except that she had fallen asleep after using a perfume sprayer. This has been seized and chloroform has been found in it; but no one seems to know who filled the sprayer with this stupefying perfume."

"Did Monsieur Havard send for you?"

"Yes, he telephoned. You know, of course, that I am always asked to intervene now in any ticklish affair!... Well Dr. Du Marvier, an expert in his way, noticed that the Princess had been half strangled by the thief in his haste to secure the pearl collar, and he wished me to search for finger prints on the nape of the victim's neck—to discover the assassin's signature in fact."

"And there were some?"

"A quantity. The Princess had been slightly wounded in the nape of the neck ... blood had been pressed on to the skin of her neck, and it was easy to take a cast of one of the fingers."

"Was that sufficient?"

"Yes, and no; such an impression is something; but there is better than that! The thief must have given the neck a violent squeeze with his hands, consequently there is a complete impression of the hand ... that I had to get...."

Fandor instinctively put his hand to his neck as if he were squeezing it. He said:

"Are such impressions imperceptible?"

"Yes; to the eye, but not to the photographing apparatus. It is thoroughly established that the pattern formed by the innumerable lines which furrow the fleshy part of our fingers is as peculiarly characteristic of each individual as the form of his nose, of his ears, or the colour of his eyes. The curves or rings, the various forms taken by these lines already exist in the newly born and never change to the day of his death. Even in case of a burn, if the skin grows again, the ridges reappear exactly as they were before the accident. Look you, one can obtain by this method—this test—such results as you would never dream of. For example, by taking these imprints I obtained in the early hours of to-day, as a basis, I can tell you, with almost absolute accuracy, the height of the individual...."

"This is marvellous!" cried Fandor. "The service your department renders then is to abolish legal blunders?"

"That is so. Every individual identified, is identified plainly, irrefutably. Unfortunately, we cannot always obtain perfect imprints on the spot where the crime is committed."

"But this night?"

"Ah, as I told you, the impressions were most satisfactory. I have the thief's hand—the whole of it! I will even go so far as to declare that the fellow who committed the crime has already been through my hands. I recognise that hand! You shall see, whether or no I have made a mistake!"...

Bertillon pressed a bell, and asked the official who answered it:

"Have you identified the imprints I sent you just now?"

"Yes, sir. This man has already been measured here. It is register 9200."

Bertillon turned to Fandor:

"You see, I was not mistaken! All I have to do is to turn up my alphabetical index, and for this very month, for the number is a recent one, and I shall know the name of the old offender—he must be one, as he is catalogued here—who has committed this assault."

Whilst speaking, Monsieur Bertillon was turning over the leaves of an enormous register:

"Ah! Here is the 9200 series!..."

Suddenly the book slipped from his hands, and he exclaimed: "The guilty man is ..."

"Is who?" questioned Fandor.

"Is Jacques Dollon!... The hand that has robbed Princess Sonia Danidoff is the hand of Jacques Dollon!"

"But it is impossible!"

Bertillon shrugged his shoulders.

"Impossible?... Why, since the proof of it is there?"

"But Jacques Dollon is dead!"

"He was the thief of yesterday's crime."

"You are making a mistake!..."

"I am not making a mistake!... Jacques Dollon is the thief I tell you!"

This was too much for JÉrÔme Fandor: he could not contain himself.

"And I tell you, Monsieur Bertillon, that I know that I am certain—positively certain, that Jacques Dollon is dead!... Now, then!..."

The man of science shook his head.

"I, in my turn, say, you are making a mistake! Look at the two imprints I have here! That of Jacques Dollon taken a few days ago, and this made from the impressions obtained this very night, or, to be exact, in the early morning hours of to-day! They are identical—one can be exactly superposed on the other!..."

"Coincidence!"

"There is no such coincidence possible—besides"—Monsieur Bertillon took up a powerful magnifying glass—"look at these characteristic details!... Just look at the lines of the thumb, all out of shape!... The presentment of the thumb itself is not normal either; it denotes habitual movement in a certain direction: it is the thumb of a painter, of a potter!... Oh, it is all as clear as daylight—believe me—there is no doubt about it! Jacques Dollon is the guilty person!"

"But," repeated Fandor obstinately: "Jacques Dollon is dead! I swear to you he is dead!..."

This assertion made no impression on the man of science.

"As to whether Jacques Dollon is alive or dead—that is for the police to decide!... For my part, I can declare that the man who committed the theft yesterday evening is the identical man who passed through my hands some days ago—and that man is certainly Jacques Dollon!"

JÉrÔme Fandor left Monsieur Bertillon. The young journalist was perplexed.... If the finger-prints on the neck of Princess Sonia Danidoff were, beyond dispute, those of Jacques Dollon—then the mystery surrounding this affair, and not this affair only, but a series of incidents, so far from being cleared up, was more impenetrable than ever!

But Fandor was obsessed by the idea of FantÔmas, of FantÔmas in the depths of mystery, presiding over this series of dramatic occurrences.

"Yes, FantÔmas is certainly in this!" he cried.... But Dollon has left traces of himself here—has, as it were, put his signature, his identification mark to this crime!... But Dollon is not FantÔmas ... besides Dollon is dead!... I have proofs of it—yes, he is dead!... Well then?...

What to make of it?

Fandor could not make anything of it!