wall of the apartment house which faced him, and make a thorough examination of it by the light of his electric torch. He judged that in the position in which he now stood he was about on a level with the floor of Ruth's room. The brick wall of the apartment building facing him was blank, that is, it contained no windows. After a minute examination, Duvall was forced to the conclusion that no entrance to the girl's bedroom had been made through it. The bricks were solid, immovable, the cemented joints firm and unbroken. A moment later he turned to the left.
Here the rising wall of the attic story of the house faced him, reaching to a point above his head. Two dusty and long unopened dormer windows, similar to those facing on the court, confronted him. He remembered that the servant of the house next door had informed him, earlier in the week, that the attic was, and long had been, unoccupied.
Whether the attic was tenanted or not, however, had no bearing on the problem which confronted him. The windows might serve as a means whereby anyone could reach the roof of the back building from the house proper, but they did not suggest any means whereby anyone might reach the windows of Ruth's bedroom. And by ascending to the point on the attic roof where his ladder stood, the problem was no nearer a solution, for a person standing there was on the edge of the court between the buildings, seven feet or more above the girl's bedroom window, and as many away from it. He turned away, and approaching the rear edge of the back building, looked over.
To his left, some eight feet away, was the fire escape before the rear window of the girl's bedroom. Standing on that sharp edge, he realized that in no way could he reach the railing of the fire escape, except by jumping, a feat that an expert gymnast might have hesitated to attempt, at that height above the ground. And could it be done successfully, what about the crash, the noise which must inevitably result from such a performance? What about the damage to the paint upon the fire escape's iron surface? And yet it would seem that a young girl had accomplished this feat, without noise, without making the least mark to register her passage. He thought of the tell-tale handkerchief, which he had found on the fire escape earlier in the evening, then turned back with a feeling of annoyance. The thing was, he realized, an impossibility.
A sudden sense of the passage of time made him hurry to the roof of the rear building of the house at No. 162. Like its neighbor, it was built with an attic story, and in the rear were two dormer windows opening in the same way upon the lower roof. Could these windows, by any chance, be those of the room of Marcia Ford? It seemed highly probable, since, if she had operated from the roof, they could afford an easy way to reach it. Very cautiously he crept up to the nearer of the two windows and looked in.
The room before him was in total darkness, and the very faint radiance from without was not sufficient to enable him to distinguish anything within it. The window, however, he saw to his delight was open, and the opening, although small, was quite large enough to enable him to crawl in. Holding his electric torch in one hand, he crept into the room.
The beam of light from his torch, although powerful, was, of course, very concentrated. He swept it about the room, to make sure that it was unoccupied. It was a small room, long and narrow, with the single dormer window, by which he had just entered, at one end, and a similar one at the side, in the slanting mansard roof. It contained a small bed, a chiffonier and dresser, a table, some chairs and a trunk. It was a woman's room; one glance at the dresser told him that, and a handkerchief lying crumpled on the latter's top proved to be identical with the one he had found on the fire escape, both in its general character, and in the initial "F" in one of its borders. Beyond any doubt, he was now in Marcia Ford's room.
Had he been inclined to doubt it, two photographs upon the wall would have convinced him. One was a picture of the Ford girl herself. The other was a portrait of the woman of the cab, the one that Duvall fully believed to be the author of the attacks upon Ruth Morton.
He examined the various articles about the room with the utmost care, but nothing of any interest rewarded his search. It had been his hope that he might find something of definite value—the typewriter, perhaps, upon which the threatening letters had been written, the black sealing wax, used in making the death's-head seals, the paper employed by the writer. None of these things was in evidence; there was no typewriter, the table contained a small bottle of ink, a couple of pens, and some cheap envelopes and a writing tablet of linen paper quite different from that upon which the warning letters had been written. There was nothing, absolutely nothing, in the place to connect its occupant with the sending of the letters, except the room's location, in such close proximity to that of Ruth Morton, and the photograph of the woman of the cab, hanging upon the wall.
Duvall, greatly disappointed, was about to take his departure, when he observed at the far end of the room a door. Whether it led to another room, or to a bathroom, or merely to a closet, he did not, of course, know. There was danger, he fully realized, that Marcia Ford might return at any moment. There was equal danger that, upon opening the door, he might find himself in another room, possibly an occupied one. He thought at one time that he heard sounds on the far side of the door, but when he paused and stood listening he could distinguish nothing, and concluded that he had been mistaken. Shutting off the light of his pocket torch for the moment, in order that, should the entrance lead to another room, its rays might not betray his presence, Duvall grabbed the door knob, and, turning it softly, opened the door.
For a moment he had a glimpse of a black cavern, and then, with incredible swiftness, something struck him a heavy blow in the face. What it was he was too much surprised and stunned to realize. His electric lamp fell from his hand, and clattered to the floor.
Realizing his helplessness in the almost total darkness, he bent down, groping about in an unsuccessful effort to recover the searchlight. And then, with a loud cry, a heavy body projected itself upon him, grasping wildly at his hair. An arm, clothed in some silken material, encircled his throat. He felt himself choking. And at the same moment a strange and irrational terror seized him. He seemed in the grasp of something uncanny, something inhuman, in spite of its very human cries. With a shudder he sprang to his feet, unable to locate the missing electric torch, and shaking the shrieking figure from him, plunged toward the window by which he had entered. It was not alone the surprise, the nameless terror of the thing, that sent Duvall headlong from the room. He fully realized that the noise of the encounter, the shrieks of his assailant, would quickly bring the other inmates of the house to the room. He had no wish to be discovered there—his entrance had been too irregular, too illegal, for that. With extraordinary rapidity he flung himself through the window and without waiting to observe the results of his intrusion, sped swiftly across the roofs of the two buildings, up the steps to the attic roof, and from there, by means of the ladder, to the roof of the apartment building. The janitor sat where he had left him, smoking a pipe. Duvall looked back. Lights were visible in the room he had just left. He saw a figure, one that closely resembled Marcia Ford, cross the lighted area of the window. There was a second figure with her—smaller, shorter, he thought. Who—what was it that had attacked him? He stood in a daze, unable to grasp the meaning of the experience through which he had just passed.
The janitor took his pipe from his mouth and rose.
"Find what you were looking for?" he asked with a grin. Duvall shook his head.
"No," he said. "Not exactly. But I'm on the track of it."
"Want the ladder any more?"
"No, not to-night." He assisted the man to draw it up to the roof.
A few moments later he had reached the sidewalk. He glanced at his watch. It was just eight o'clock. As he walked toward the entrance of the house at No. 162, the front door opened, and a woman came out.
Duvall quickened his pace, but the woman was also apparently in a great hurry. She ran swiftly across the sidewalk, and sprang into a cab which stood beside the curb. Duvall was able to get but a fleeting glance at her, but that glance was enough to convince him that
