parently significant a paper to the office. Her failure to do so was neither logical nor reasonable; and I ought to have been suspicious. But—my word!—what was one illogical item more or less in such a mélange of inconsistencies? As it happened, her decoy worked beautifully, and gave her the opportunity to telephone Rex to look into the chute. But it didn't really matter. If the scheme had fallen through that morning, it would have been successful later on. Ada was highly persevering."
"You think then," put in Markham, "that Rex really heard the shot in Ada's room that first night, and confided in her?"
"Undoubtedly. That part of her story was true enough. I'm inclined to think that Rex heard the shot and had a vague idea Mrs. Greene had fired it. Being rather close to his mother temperamentally, he said nothing. Later he voiced his suspicions to Ada; and that confession gave her the idea for killing him—or, rather, for perfecting the technic she had already decided on; for Rex would have been shot through the secret cupboard in any event. But Ada now saw a way of establishing a perfect alibi for the occasion; although even her idea of being actually with the police when the shot was fired was not original. In Gross's chapter on alibis there is much suggestive material along that line."
Heath sucked his teeth wonderingly.
"I'm glad I don't run across many of her kind," he remarked.
"She was her father's daughter," said Vance. "But too much credit should not be given her, Sergeant. She had a printed and diagrammed guide
