Tarling put his light into the hall and saw the carpeted stairs half-a-dozen feet away. He guessed what had happened. Somebody had seen the door ajar, and guessing from the fact that she had left it open that she was returning immediately, had slipped a piece of wood, which looked to be and was in fact the stalk of a match, between the catch of the spring lock and its sheath.
"What has happened?" asked the girl in a troubled voice.
"Nothing," said Tarling airily. "It was probably your disreputable step-father did this. He may have lost his key."
"He could have gone in the front door," said the girl uneasily.
"Well, I'll go first," said Tarling with a cheerfulness which he was far from feeling.
He went upstairs, his lamp in one hand, an automatic pistol in the other. The stairs ended in a balustraded landing from which two doors opened.
"That is mother's room," said the girl, pointing to the nearest.
A sense of impending trouble made her shiver. Tarling put his arms about her encouragingly. He walked to the door of the room, turned the handle and opened it. There was something behind the door which held it close, and exerting all his strength he pushed the door open sufficiently far to allow of his squeezing through.
On the desk a table-lamp was burning, the light of which was hidden from the outside by the heavily-curtained windows, but it was neither at the window nor at the desk that he was looking.
Mrs. Rider lay behind the door, a little smile on her face, the haft of a dagger standing out with hideous distinctness beneath her heart.