“She is the one person who must not know,” he said emphatically. “If it were not for her—” he shrugged his shoulders, “you might see it.”
Carver knew that he was opposed by a will greater than his own and that neither threats nor promises would move this impassive man from the attitude he had taken up.
“What does it matter whether you see this paper or not?” asked Yeh Ling. “You say you know the murderer, that you have sufficient evidence to put him on the trap—but have you?”
His look was a challenge.
“You cannot convict a man on supposition, Mr. Carver. You must prove beyond any doubt whatever that Jesse Trasmere was killed by somebody who had the means of getting in and out that locked vault, and leaving the key on the table. It is not enough to say: ‘I am certain that this prisoner killed his—benefactor.’ It is not sufficient that you can show motives. You must produce the means! Until you can say the murderer obtained admission to the vault by this or that door, in this or that way, or that he employed these or those means to restore the key to the table from the outside of a locked door through which no key could pass, you cannot secure a conviction. That is the law. I studied law at Harvard, and I have the rules of evidence at my fingertips,” he smiled faintly. “You see, Mr. Carver, that the confirmatory evidence you require cannot possibly be supplied by me.”
Carver knew that he was speaking no more than the truth; that he was against a dead wall unless some human eye had witnessed the murder, and the method by which the murderer escaped.
The logic of the Chinaman’s criticism was irresistible, and Carver, who had seen success within reach, experienced a sense of failure at the very moment when he thought that all his efforts were coming to fruition.
“Then tell me this,” he said. “I understand that on several occasions you have been followed by this Man in Black. Have you any idea who he is?”
“Yes,” said the other without hesitation, “but what is the value of my ideas? I could not swear to any facts, and facts are the meat and drink of juries, Mr. Carver.”
Carver got up and sighed heavily, and hearing him Yeh Ling broke into a fit of silent laughter.