The new-comer was a newspaper boy, who pushed a bundle of evening papers through the iron bars and went off again. Tarling waited until he heard the door of the cottage or lodge close. Then he made a circuit of the house, hoping to find another entrance. There was evidently a servants' entrance at the back, leading from the lane, but this too was closed. Throwing his light up, he saw that there was no broken glass on top of the wall, as there had been in the front of the house, and, making a jump, he caught the stone coping and drew himself up and astride.
He dropped into the darkness on the other side without any discomfort to himself, and made his cautious way towards the house. Dogs were the danger, but apparently Mrs. Rider did not keep dogs, and his progress was unchallenged.
He saw no light either in the upper or lower windows until he got to the back. Here was a pillared-porch, above which had been built what appeared to be a conservatory. Beneath the porch was a door and a barred window, but it was from the conservatory above that a faint light emanated. He looked round for a ladder without success. But the portico presented no more difficulties than the wall had done. By stepping on to the window-sill and steadying himself against one of the pillars, he could reach an iron stanchion, which had evidently been placed to support the framework of the superstructure. From here to the parapet of the conservatory itself was but a swing. This glass-house had casement windows, one of which was open, and he leaned on his elbows and cautiously intruded his head.
The place was empty. The light came from an inner room opening into the glass sheltered balcony. Quickly he slipped through the windows and crouched under the shadow of a big oleander. The atmosphere of the conservatory was close and the smell was earthy. He judged from the hot-water pipes which his groping hands felt that it was a tiny winter garden erected by the owner of the house for her enjoyment in the dark, cold days. French windows admitted to the inner room, and, peering through the casement curtains which covered them, Tarling saw Mrs. Rider. She was sitting at a desk, a pen in her hand, her chin on her finger-tips. She was not writing, but staring blankly at the wall, as though she were at a loss for what to say.
The light came from a big alabaster bowl hanging a foot below the ceiling level, and it gave the detective an opportunity of making a swift examination. The room was furnished simply if in perfect taste, and had the appearance of a study. Beside her desk was a green safe, half let into the wall and half exposed. There were a few prints hanging on the walls, a chair or two, a couch half hidden from the detective's view, and that was all. He had expected to see Odette Rider with her mother, and was disappointed. Not only was Mrs. Rider alone, but she conveyed the impression that she was practically alone in the house.
Tarling knelt, watching her, for ten minutes, until he heard a sound outside. He crept softly back and looked over the edge of the portico in time to see a figure moving swiftly along the path. It was riding a bicycle which did not carry a light. Though he strained his eyes, he could not tell whether the rider was man or woman. It disappeared under the portico and he heard the grating of the machine as it was leant against one of the pillars, the click of a key in the lock and the sound of a door opening. Then he crept back to his observation post overlooking the study.
Mrs. Rider had evidently not heard the sound of the door opening below, and sat without movement still staring at the wall before her. Presently she started and looked round towards the door. Tarling noted the door—noted, too the electric switch just in view. Then the door opened slowly. He saw Mrs. Rider's face light up with pleasure, then somebody asked a question in a whisper, and she answered—he could just hear her words:
"No darling, nobody."
Tarling held his breath and waited. Then, of a sudden, the light in the room was extinguished. Whoever had entered had turned out the light. He heard a soft footfall coming towards the window looking into the conservatory and the rattle of the blinds as they were lowered. Then the light went up again, but he could see nothing or hear nothing.
Who was Mrs. Rider's mysterious visitor? There was only one way to discover, but he waited a little longer—waited, in fact, until he heard the soft slam of a safe door closing—before he slipped again through the window and dropped to the ground.