The lock grated with an uneasy sound and the door swung slowly inward. Still, black darkness, which could almost be felt, confronted him. Peter stepped across the threshold, and without a sound, carefully shut the door. The closed rooms, after the oppressive heat of the outer world, seemed damp and cold, and Peter shivered slightly. In his rubber-soled shoes he made no sound as he advanced into the living room, flashing his light carefully about to avoid colliding with anything. There was little fear of being seen from the outside, since the buildings opposite were used for business purposes, and empty at this time of night, but Peter was taking no chances. His first move was to pull down the dark shades at the windows. Remembering the way the outer halls were lighted, he struck a match to light the gas, and found, to his surprise, that the apartment was equipped with electricity. He had not noticed it before, or if he had, it had made no impression on his then preoccupied mind. He saw nothing significant in it now--was glad of the more brilliant light in which to make his investigation--that was all. There was a candle lamp over on the desk and a big, shaded lamp upon the table. Peter switched on the smaller lamp. In the quiet light which illumined the room he could see that it was just as he had left it over three weeks before. A little dust had drifted in through the chinks of the windows, filming the polished mahogany of table, chairs, and couch, but otherwise there was no change, except that the scarf, which had proved an open sesame to a world of anxiety, had been removed. But Peter knew all about that. He, himself, had taken it to VanDorn and Sawyer to have the stain upon it analyzed. They found it to be, what he felt sure from the first it was, human blood. The scarf lay, now, in the safe at his office. Peter went into the bedroom and pulled down the shade, lest some wakeful person in the houses on the street above might catch a gleam from the light which he had left burning in the living room, and become curious. Then, softly, he crept into the dining room and lowered the blinds there, then into the kitchen, where he noted that the broken pane of glass had been replaced according to Morris's careful instructions to Angelo on the day it was discovered. He had felt, with Morris, that it was an unnecessary risk to leave it in a condition in which any sneak thief might have entered from the fire-escape with perfect ease. Peter drew the dark blue blind down to the sill, and flashed the cold eye of his hand-torch about, looking for a light fixture. He found it in the shape of an old-fashioned gas chandelier with two burners, suspended from the ceiling. He lit them both. The gas burned high, with a soft, secret hiss. It sounded loud in the remote stillness of the place, and automatically Peter lowered it to the point of silence.