Mr. Sabin nodded.

“I am perfectly willing,” he said, “to answer any questions you may choose to put to me.”

A plain, hard-featured little man, in a long black overcoat, and holding a bowler hat in his hand, bowed respectfully to Mr. Sabin.

“I am much obliged to you, sir,” he said.  “My name is John Passmore.  We do not of course appear in this matter unless the post-mortem should indicate anything unusual in the circumstances of Duson’s death, but it is always well to be prepared, and I ventured to ask Mr. Hertz here to procure for me your opinion as regards the death of your servant.”

“You have asked me,” Mr. Sabin said gravely, “a very difficult question.”

The eyes of the little detective flashed keenly.

“You do not believe then, sir, that he died a natural death?”

“I do not,” Mr. Sabin answered.

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 circumstances 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—­”