"Then when Mr. Haken retired, Sir Oliver burned the herb in a shallow bronze cup--the same as Mr. Shepworth saw in his flat--and went into a trance. Madame Marie had arranged with Agstone that he should watch at the window until Sir Oliver was insensible, and then kill him. The man did so with the jade-handled paper-knife." "Why wasn't Agstone stifled with the smoke fumes?" "Because the smoke had died away. When Sir Oliver was dead, Agstone heard a step, and, after setting fire to some more leaves, he ran out of the window, not the one opened by Miss Chent, but another one. He watched, and saw Miss Chent enter; saw also how she fainted with the acrid smoke. He entered, and placed her in the armchair where she was found. It was then that Madame Marie came downstairs and into the room. She snatched up the third will, at which Sir Oliver had been looking, before manipulating the herb, and tearing it up, flung it into the fire. Then she gave the will leaving everything to Miss Chent--which Lanwin had also been looking at to destroy, I presume--to Agstone, and told him to take it up to his brother, Dr. Horace." "What for?" asked Prelice, surprised. "Madame Marie said she had no grudge against Miss Chent," explained Martaban, "and wanted the will placed safely out of Jadby's way, so that Miss Chent might inherit, and that Jadby might be kept poor." "One for Mona and two for herself," said Prelice grimly. "But who placed the knife in Mona's hand?" "Agstone, who hated her, did. A step was heard--that was Shepworth coming down--so Madame Marie ran out of the window, and got back to her room by another door, which Agstone had left open. The man waited to smear Miss Chent's dressing-gown with blood and to place the knife in her hand. Then Mr. Shepworth--so he says--secured the knife, and----" "I know all that," said Prelice, "and understand the why and the wherefore of the first crime. But the second?" "That arose out of Jadby's hatred for Shepworth and his love for Miss Chent. Jadby learned the truth about the crime from Agstone, whom he found hiding in London, under the protection of Madame Marie. He threatened to denounce him to the police to save Miss Chent, and then resolved to make use of him to incriminate Shepworth, and, at the same time, to kill him, so that he might not come forward to give evidence against Miss Chent, which Agstone wanted to do." "But surely he would not have accused Mona of a crime which he had committed himself?" said Prelice indignantly. "Yes, he would," said Ned quickly; "he hated Mona, and Sir Oliver, and Madame Marie, and Jadby, and everyone. The man was a Caliban; and to tell you the truth," added Shepworth candidly, "I don't think that his brother is much better." "Ah!" said Prelice suddenly, "did Agstone confess the truth to Horace?"