Still, his investigations in Miss Ford's room had not been entirely fruitless, although they had also added a startlingly new element to the mystery of the case. Who was the person who had attacked him from the closet? Was it the woman who had just left the house? He did not think so. Nor was it Miss Ford herself. There had been something uncanny about the whole experience; he was by no means certain that his assailant had been a human being at all. And yet, its cries--its fingers, tearing at his throat. He was unable to account for the experience at all, and determined, as soon as possible, to repeat his visit, and sift the matter to the bottom. He remembered that he had seen two persons in the Ford girl's room, after his hasty retreat. Two women, he thought, outlined against the lighted square of the window. One of these had already left the house. The other, Miss Ford herself, was still there. He determined to interview her at once. Of course, he told himself, to do so would put her on her guard, but his visit to her room had already done that, and doubtless accounted for her companion's hasty flight. And there was something to be gained, by letting her realize that she was under suspicion. She would at once try to communicate with, to warn, her confederate, and it was in just such ways as this, Duvall's experience told him, that criminals so often betrayed themselves. If, by frightening Miss Ford, he could cause her to flee--to join her companion--the tracing of the latter would become comparatively simple. He went up to the door of No. 162 and rang the bell. The same woman answered his summons as had answered before. She seemed somewhat uneasy--disturbed. "I want to see Miss Marcia Ford," Duvall told her. "Very well, sir. Come in. I will tell Miss Ford. What name, please?" "Say that Mr. Bradley is calling." The girl ushered him into a dark parlor, lighted by a single lowered gas jet, and suggestive of the gloom of ages, in its walnut furniture, its dismal pictures and ornaments. He took a seat, and waited for the appearance of Miss Ford. She arrived in a few moments, a slender, ordinary-looking girl, in white shirtwaist and black skirt. "You are Mr. Bradley?" she asked, regarding the detective with a look of inquiry. "Yes. I came to see you about a matter of importance." "What is it?" "Who was the woman who just left here--the woman who had just come in with you?" Miss Ford favored the detective with a glassy stare. "I do not understand you," she exclaimed. "I came home alone. What is the purpose of these questions?" Duvall felt that he had a shrewd opponent to deal with. "Are you acquainted with Miss Ruth Morton?" he asked. "Why--certainly--that is, I know her by reputation, She works for the same company as I do. Why do you ask?" "Miss Morton has recently been the subject of a shameful persecution. The woman who just left this house is concerned in it. Who is she?"