Mr. Hertz was startled. The detective controlled his features admirably.

"May I ask your reasons, sir?"

Mr. Sabin lightly shrugged his shoulders.

"I have never known the man to have a day's illness in his life," he said. "Further, since his arrival in England he has been acting in a strange and furtive manner, and I gathered that he had some cause for fear which he was indisposed to talk about."

"This," the detective said, "is very interesting."

"Doubtless," Mr. Sabin answered. "But before I say anything more I must clearly understand my position. I am giving you personally a few friendly hints, in the interests of justice perhaps, but still quite informally. I am not in possession of any definite facts concerning Duson, and what I say to you here I am not prepared to say at the inquest, before which I presume I may have to appear as a witness.

There, I shall do nothing more save identify Duson and state the circ.u.mstances under which I found him."

"I understand that perfectly, sir," the man answered. "The less said at the inquest the better in the interests of justice."

Mr. Sabin nodded.

"I am glad," he said, "that you appreciate that. I do not mind going so far then as to tell you that I believe Duson died of poison."

"Can you give me any idea," the detective asked, "as to the source?"

"None," Mr. Sabin answered. "That you must discover for yourselves.

Duson was a man of silent and secretive habits, and it has occurred to me more than once that he might possibly be a member of one of those foreign societies who have their headquarters in Soho, and concerning which you probably know more than I do."

The detective smiled. It was a very slight flicker of the lips, but it attracted Mr. Sabin's keen attention.

"Your suggestions," the detective said, "are making this case a very interesting one. I have always understood, however, that reprisals of this extreme nature are seldom resorted to in this country. Besides, the man's position seems scarcely to indicate sufficient importance--perhaps--"

"Well?" Mr. Sabin interjected.

"I notice that Duson was found in your sitting-room. It occurs to me as a possibility that he may have met with a fate intended for some one else--for yourself, for instance, sir!"

"But I," Mr. Sabin said smoothly, "am a member of no secret society, nor am I conscious of having enemies sufficiently venomous to desire my life."

The detective sat for a moment with immovable face.

"We, all of us, know our friends, sir," he said. "There are few of us properly acquainted with our enemies."

Mr. Sabin lit a cigarette. His fingers were quite steady, but this man was making him think.

"You do not seriously believe," he asked, "that Duson met with a death which was intended for me?"

"I am afraid," the detective said thoughtfully, "that I know no more about it than you do."

"I see," Mr. Sabin said, "that I am no stranger to you."

"You are very far from being that, sir," the man answered. "A few years ago I was working for the Government--and you were not often out of my sight."

Mr. Sabin smiled.

"It was perhaps judicious," he remarked, "though I am afraid it proved of very little profit to you. And what about the present time?"

"I see no harm in telling you, sir, that a general watch is kept upon your movements. Duson was useful to us... but now Duson is dead."

"It is a fact," Mr. Sabin said impressively, "that Duson was a genius.

My admiration for him continually increases."

"Duson made harmless reports to us as we desired them," the detective said. "I have an idea, however, that if this course had at any time been inimical to your interests that Duson would have deceived us."

"I am convinced of it," Mr. Sabin declared.

"And Duson is dead!"

Mr. Sabin nodded gravely.

The little hard-visaged man looked steadily for a moment upon the carpet.

"Duson died virtually whilst accepting pay from if not actually in the employ of our Secret Service Department. You will understand, therefore, that we, knowing of this complication in his life, naturally incline towards the theory of murder. Shall I be taking a liberty, sir, if I give you an unprofessional word of warning?"

Mr. Sabin raised his eyebrows.

"By no means," he answered. "But surely you cannot--"

The man smiled.

"No, sir," he said drily. "I do not for one moment suspect you. The man was our spy upon your movements, but I am perfectly aware that there has been nothing worth reporting, and I also know that you would never run such a risk for the removal of so insignificant a person. No, my warning comes to you from a different point of view. It is, if you will pardon my saying so, none the less personal, but wholly friendly. The case of Duson will be sifted to the dregs, but unless I am greatly mistaken, and I do not see room for the possibility of a mistake, I know the truth already."

"You will share your knowledge?" Mr. Sabin asked quietly.

The detective shook his head.

"You shall know," he said, "before the last moment. But I want to warn you that when you do know it--it will be a shock to you."

Mr. Sabin stood perfectly still for several moments. This little man believed what he was saying. He was certainly deceived. Yet none the less Mr. Sabin was thoughtful.

"You do not feel inclined," he said slowly, "to give me your entire confidence."

"Not at present, sir," the man answered. "You would certainly intervene, and my case would be spoilt."

Mr. Sabin glanced at the clock.

"If you care to call on me to-morrow," he said, "I could perhaps show you something which might change your opinion."

The detective bowed.

"I am always open, sir," he said, "to conviction. I will come about twelve o'clock."

Mr. Sabin went back to the palm lounge. Lucille and Reginald Brott were sitting together at a small table, talking earnestly to one another.

The Prince and Lady Carey had joined another party who were all talking together near the entrance. The latter, directly she saw them coming, detached herself from them and came to him.