"But you thought you heard her," he cried; "her voice, or her laugh, or perhaps merely the rustle of her dress in another room?"
"No," said Mansell, "I didn't hear her."
"Of course not," was the instantaneous reply. "But something said or done by somebody—a something which amounts to nothing as evidence—gives you to understand she was there, and so you hold your tongue for fear of compromising her."
"Amounts to nothing as evidence?" echoed Mansell. "How do you know that?"
"Because Miss Dare was not in the house with your aunt at that time. Miss Dare was in Professor Darling's observatory, a mile or so away."
"Does she say that?"
"We will prove that."
Aroused, excited, the prisoner turned his flashing blue eyes on the detective.
"I should be glad to have you," he said.
"But you must first tell me in what room you were when you received this intimation of Miss Dare's presence?"