we have sufficient evidence to arrest van Heerden. The tile from the Grand Alliance shows traces of digitalis."
Beale shook his head.
"The case would fall," he said. "What evidence have you? We did not confiscate his medicine-case. He might have dropped a tablet of digitalis by accident. The only evidence you could convict van Heerden on is proof that he brought with him cyanide tablets which he slipped into Prédeaux's pocket. No, we can prove nothing."
"What is your theory in connection with the crime?"
"I have many theories," said Mr. Beale, rising and pacing the room, "and one certainty. I am satisfied that Millinborn was killed by Doctor van Heerden. He was killed because, during the absence of Mr. Kitson in the village, the doctor forced from the dying man a secret which up till then he had jealously preserved. When Kitson returned he found his friend, as he thought, in extremis, and van Heerden also thought that John Millinborn would not speak again. To his surprise Millinborn did speak and van Heerden, fearful of having his villainy exposed, stabbed him to the heart under the pretext of assisting him to lie down.
"Something different occurred at the Grand Alliance Hotel. A man swoons, immediately he is picked up by the doctor, who gives him a harmless drug—that is to say, harmless in small quantities. In five seconds the man is dead. At the inquest we find he has been poisoned—cyanide is found in his pocket. And who is this man? Obviously the identical person who witnessed the murder of John Millinborn and whom we have been trying to find ever since that crime."
"Van Heerden won't escape the third time. His presence will be a little more than a coincidence," said the superintendent.
Beale laughed.
"There will be no third time," he said shortly, "van Heerden is not a fool."
"Have you any idea what the secret was that he wanted to get from old Millinborn?" asked the detective.
