He glanced upward. The fire escaped stopped at the level of the floor above. To ascend from it to the roof was impossible.
Remembering that the top apartment was vacant, Duvall re-entered the building and hunting up the janitor, told him that he desired to get out on the roof.
The man remembered him, from his first visit, and the inquiries he had then made about the tenants of the apartment above.
"I am making some special inquiries on Mrs. Morton's behalf," he explained. "You can go with me, if you like, to see that I do nothing I shouldn't."
"I'm not worrying," he rejoined, "but I'll go along, just the same, to show you the way." He led the detective up one flight of stairs and, going to the end of the outer hall, unlocked and opened a small door beside the elevator shaft. A short spiral staircase was disclosed.
Snapping on an electric light, the man ascended the steps, and, after fumbling for a moment with the catch, threw open a trapdoor leading to the roof. In a moment both he and Duvall had climbed out upon the tiled surface. Duvall went to the edge which overlooked the house adjoining, and peered down. He at once saw something that interested him.
The house with the dormer windows consisted, as has been previously mentioned, of four stories and an attic. Its roof rose several feet above the level of the window of Ruth's room, which was on the fourth floor of the apartment building. But Duvall saw at once that this elevation of the adjoining house did not extend all the way back, but, in fact, stopped a little beyond the point where it joined the apartment. From here to the rear of the lot the building had no attic, its rear extension being but four stories high. In this position on the apartment-house roof, the roof of the back building was at least fifteen feet below him.
Another thing that he noticed at once was the fact that the second house, No. 162, was of almost the same design as the first, that is, it consisted of a main building with an attic, and a rear extension, reaching to the same level as that of the house between. It was clear that if anyone living in the second house could obtain access to the roof of the back building, he would be able to walk across that of the first or adjoining house, and reach a point directly beneath where he stood.