"Then we must accept her terms. She can be shadowed?"
"Every moment."
"Very well, then. Extreme cases must be met by extreme measures. We will let her have her swing, and see what comes of it. Revenge is a great weapon in the hands of a determined woman, and from her look I think she will make the most of it."
And returning to where the young girl stood, the Superintendent asked her whether she felt sure the murderer would not escape in the time that must elapse before his apprehension.
Instantly her cheek, which had looked as if it could never show color again, flushed a deep and painful scarlet, and she cried vehemently:
"If any hint of what is here passing should reach him I should be powerless to prevent his flight. Swear, then, that my very existence shall be kept a secret between you two, or I will do nothing towards his apprehension,—no, not even to save the innocent."
"We will not swear, but we will promise," returned the Superintendent. "And now, when may we expect to hear from you again?"
"Two weeks from to-night as the clock strikes eight. Be wherever I may chance to be at that hour, and see on whose arm I lay my hand. It will be that of the man who killed Mrs. Van Burnam."