Duvall glanced over to where Mrs. Morton hung in agonized silence over her daughter's bed, then went out into the sitting room. It seemed to him well nigh incredible that the woman responsible for all this had been able to move about, to elude pursuit, to carry out her threats, apparently without the least hesitation or fear of capture. His professional pride had received severe shock.
Two means of finding the woman, he felt, were still open to him. One was to trace her through Miss Ford. He did not doubt that, after what he had said to the latter, she would make an immediate attempt to warn her confederate of the danger that threatened her. Of course, the Ford girl might communicate with her companion by telephone, in which event the tracing would be difficult, if not impossible.
The other hope of tracing the woman lay in Grace. Why had she left the hotel so suddenly? He did not of course know the source of the telephone message, and could only surmise that Grace had in some way been able to pick up the woman's trail.
Leaving Mrs. Morton with a few words of encouragement, he made his way to his hotel. There was no news there of Grace, however, and he realized that it was now too late to accomplish anything by returning to the house on 57th Street. Marcia Ford would either have long since retired, or else would have left the house to communicate with the woman who had been with her earlier in the evening. Considerably upset by the events of the past three hours, Duvall retired to his room, and sat down to think the whole matter over.
Proceeding on the assumption that the woman in question, and Miss Ford were acting together, all the events at the studio, the fake telegram, the missing photograph, became intelligible. But the delivery of the letters in Ruth Morton's apartment, the strange attack upon him while searching the Ford girl's room, were by no means so clear. Once more his thoughts reverted to the attic room, the roof of the adjoining house, the problem of effecting an entrance to the Morton apartment through either of the two windows.
And then, as he revolved the problem in his mind, a sudden light came to him. He sprang from his chair with an exclamation of satisfaction. A solution of the whole matter flashed through his brain, a solution at once so simple, and so ingenious, that he wondered he had not thought of it before.
He glanced at his watch. It was midnight. Too late, perhaps, to test the accuracy of his deductions. Nor did he feel at all easy in his mind regarding Grace. Something must have happened to her, he feared, to keep her out so late, with no word to him concerning her movements. He went to the 'phone, and calling up the office, inquired whether anything had been heard of Mrs. Duvall.
"No," the night clerk informed him. Mrs. Duvall had not been heard from, nor had she sent any message. But a note had just been left for her. He would send it up.
Duvall awaited the arrival of the note with the utmost impatience. A message for Grace. From whom? What could it mean? A few moments later one of the bellboys thrust into his hand a letter, written on the note paper of the hotel.
He regarded the scrawling and ill-written superscription with apprehension, then tore open the envelope and proceeded to read the contents of the note.