"And suppose he does not come?" M. Desmalions once more exclaimed, in a more vehement tone.

"Then, Monsieur le Prefet, you may take it that I am the culprit; and you have only to arrest me. This day, between five and six o'clock, you will see before you, in this room, the person who killed the Mornington heirs.

It is, humanly speaking, impossible that this should not be so.

Consequently, the law will be satisfied in any circ.u.mstances. He or I: the position is quite simple."

M. Desmalions was silent. He gnawed his moustache thoughtfully and walked round and round the table, within the narrow circle formed by the others.

It was obvious that objections to the supposition were springing up in his mind. In the end, he muttered, as though speaking to himself:

"No, no. For, after all, how are we to explain that the man should have waited until now to claim his rights?"

"An accident, perhaps, Monsieur le Prefet, an obstacle of some kind. Or else--one can never tell--the perverse longing for a more striking sensation. And remember, Monsieur le Prefet, how minutely and subtly the whole business was worked. Each event took place at the very moment fixed by Hippolyte Fauville. Cannot we take it that his accomplice is pursuing this method to the end and that he will not reveal himself until the last minute?"

M. Desmalions exclaimed, with a sort of anger:

"No, no, and again no! It is not possible. If a creature monstrous enough to commit such a series of murders exists, he will not be such a fool as to deliver himself into our hands."

"Monsieur le Prefet, he does not know the danger that threatens him if he comes here, because no one has even contemplated the theory of his existence. Besides, what risk does he run?"

"What risk? Why, if he has really committed those murders--"

"He has committed them, Monsieur le Prefet. He has _caused_ them to be committed, which is a different thing. And you now see where the man's unsuspected strength lies! He does not act in person. From the day when the truth appeared to me, I have succeeded in gradually discovering his means of action, in laying bare the machinery which he controls, the tricks which he employs. He does not act in person.

There you have his method. You will find that it is the same throughout the series of murders.

"In appearance, Cosmo Mornington died of the results of a carelessly administered injection. In reality, it was this man who caused the injection to prove fatal. In appearance, Inspector Verot was killed by Hippolyte Fauville. In reality, it must have been this man who contrived the murder by pointing out the necessity to Fauville and, so to speak, guiding his hand. And, in the same way, in appearance, Fauville killed his son and committed suicide; Marie Fauville committed suicide; Gaston Sauverand committed suicide. In reality, it was this man who wanted them dead, who prompted them to commit suicide, and who supplied them with the means of death.

"There you have the method, and there, Monsieur le Prefet, you have the man." And, in a lower voice, that contained a sort of apprehension, he added, "I confess that never before, in the course of a life that has been full of strange meetings, have I encountered a more terrifying person, acting with more devilish ability or greater psychological insight."

His words created an ever-increasing sensation among his hearers. They really saw that invisible being. He took shape in their imaginations.

They waited for him to arrive. Twice Don Luis had turned to the door and listened. And his action did more than anything else to conjure up the image of the man who was coming.

M. Desmalions said:

"Whether he acted in person or caused others to act, the law, once it has hold of him, will know how to--"

"The law will find it no easy matter, Monsieur le Prefet! A man of his powers and resource must have foreseen everything, even his arrest, even the accusation of which he would be the subject; and there is little to be brought against him but moral charges without proofs."

"Then you think--"

"I think, Monsieur le Prefet, that the thing will be to accept his explanations as quite natural and not to show any distrust. What you want is to know who he is. Later on, before long, you will be able to unmask him."

The Prefect of Police continued to walk round the table. Major d'Astrignac kept his eyes fixed on Perenna, whose coolness amazed him.

The solicitor and the secretary of Emba.s.sy seemed greatly excited. In fact nothing could be more sensational than the thought that filled all their minds. Was the abominable murderer about to appear before them?

"Silence!" said the Prefect, stopping his walk.

Some one had crossed the anteroom.

There was a knock at the door.

"Come in!"

The office messenger entered, carrying a card-tray. On the tray was a letter; and in addition there was one of those printed slips on which callers write their name and the object of their visit.

M. Desmalions hastened toward the messenger. He hesitated a moment before taking up the slip. He was very pale. Then he glanced at it quickly.

"Oh!" he said, with a start.

He looked toward Don Luis, reflected, and then, taking the letter, he said to the messenger:

"Is the bearer outside?"

"In the anteroom, Monsieur le Prefet."

"Show the person in when I ring."

The messenger left the room.

M. Desmalions stood in front of his desk, without moving. For the second time Don Luis met his eyes; and a feeling of perturbation came over him.

What was happening?

With a sharp movement the Prefect of Police opened the envelope which he held in his hand, unfolded the letter and began to read it.

The others watched his every gesture, watched the least change of expression on his face. Were Perenna's predictions about to be fulfilled?

Was a fifth heir putting in his claim?

The moment he had read the first lines, M. Desmalions looked up and, addressing Don Luis, murmured:

"You were right, Monsieur. This is a claim."

"On whose part, Monsieur le Prefet?" Don Luis could not help asking.

M. Desmalions did not reply. He finished reading the letter. Then he read it again, with the attention of a man weighing every word. Lastly, he read aloud:

"MONSIEUR LE PReFET:

"A chance correspondence has revealed to me the existence of an unknown heir of the Roussel family. It was only to-day that I was able to procure the doc.u.ments necessary for identifying this heir; and, owing to unforeseen obstacles, it is only at the last moment that I am able to send them to you _by the person whom they concern_. Respecting a secret which is not mine and wishing, as a woman, to remain outside a business in which I have been only accidentally involved, I beg you, Monsieur le Prefet, to excuse me if I do not feel called upon to sign my name to this letter."

So Perenna had seen rightly and events were justifying his forecast. Some one was putting in an appearance within the period indicated. The claim was made in good time. And the very way in which things were happening at the exact moment was curiously suggestive of the mechanical exactness that had governed the whole business.

The last question still remained: who was this unknown person, the possible heir, and therefore the five or six fold murderer? He was waiting in the next room. There was nothing but a wall between him and the others. He was coming in. They would see him. They would know who he was.

The Prefect suddenly rang the bell.

A few tense seconds elapsed. Oddly enough, M. Desmalions did not remove his eyes from Perenna. Don Luis remained quite master of himself, but restless and uneasy at heart.

The door opened. The messenger showed some one in.

It was Florence Leva.s.seur.