Seton paused.  Margaret was biting her lip hard, and Rita was looking down so that her face could not be seen.

“The shock consequent upon the deed sobered the half crazy woman,” continued the speaker.  “Her usual resourcefulness returned to her.  Self-preservation had to be considered before remorse.  Mrs. Irvin had swooned, and”—­he hesitated—­“Mrs. Sin saw to it that she did not revive prematurely.  Mareno was summoned from the room above.  The outer door was locked.

“It affords evidence of this woman’s callous coolness that she removed from the Kazmah premises, and—­probably assisted by her brother, although he denies it—­from the person and garments of the dead man, every scrap of evidence.  They had not by any means finished the task when you knocked at the door, Gray.  But they completed it, faultlessly, after you had gone.

“Their unconscious victim, and the figure of Kazmah, as well as every paper or other possible clue, they carried up to the Cubanis office, and from thence across the roof to Sir Lucien’s study.  Next, while Mareno went for the car, Mrs. Sin rifled the safe, bureaus and desks in Sir Lucien’s flat, so that we had the devil’s own work, as you know, to find out even the more simple facts of his everyday life.

“Not a soul ever came forward who noticed the big car being driven into Albemarle Street or who observed it outside the flat.  The chances run by the pair in conveying their several strange burdens from the top floor, down the stairs and out into the street were extraordinary.  Yet they succeeded unobserved.  Of course, the street was imperfectly lighted, and is but little frequented after dusk.

“The journey to Limehouse was performed without discovery—­aided, no doubt, by the mistiness of the night; and Mareno, returning to the West End, ingeniously inquired for Sir Lucien at his club.  Learning, although he knew it already, that Sir Lucien had not been to the club that night, he returned the car to the garage and calmly went back to the flat.

“His reason for taking this dangerous step is by no means clear.  According to his own account, he did it to gain time for the fugitive Mrs. Sin.  You see, there was really only one witness of the crime (Mrs. Irvin) and she could not have sworn to the identity of the assassin.  Rashid was warned and presumably supplied with sufficient funds to enable him to leave the country.

“Well, the woman met her deserts, no doubt at the hands of Sin Sin Wa.  Kerry is sure of this.  And Sin Sin Wa escaped, taking with him an enormous sum of ready money.  He was the true genius of the enterprise.  No one, his wife and Mareno excepted—­we know of no other—­suspected that the real Sin Sin Wa was clean-shaven, possessed two eyes, and no pigtail!  A wonderfully clever man!”

The native servant appeared to announce that dinner was served; African dusk drew its swift curtain over the desert, and a gun spoke sharply from the Citadel.  In silence the party watched the deepening velvet of the sky, witnessing the birth of a million stars, and in silence they entered the gaily lighted dining-room.