eived. But it has one
weakness. You are not sure that the murderer _did_ ascend to the roof
after the crime. He may have been lurking in the shadows which you say
were lying so thickly at the end of the hall. He may have been
watching you as you discovered the body, while you ran down the hall
once more and down the stairs. To be sure, you slammed the door behind
you; and so locked it. But like all spring or latch locks, it could be
readily opened from the inside. No one else came out while the cab
driver waited; but that was only for another fifteen minutes,
according to his own statement. The murderer could easily have waited
until he had gone and then slipped out, also locking the door after
him."

Miss Vale sat staring at the speaker dumbly for a space; then she
asked in a dry, expressionless way:

"And do you really think this is what happened?"

Ashton-Kirk shook his head.

"No," said he. "I merely mentioned it to show you that it is difficult
to be sure of anything in a matter like this until," with a smile,
"you _are_ sure. It is one of the things that may have happened; but
it is also open to question. A criminal whose crime has been
discovered does not ordinarily linger upon the scene. You had just
fled with the terror of the thing fresh upon you. How did he know but
that you might scream it out to everyone you met."

Again she looked at him mutely. Then she said:

"What, then, is your theory of the crime?"

"I have a number of possibilities at this moment," he said. "Of
course, there is one to which I give the preference; but until a thing
is proven beyond question, it is my rule never to outline my
theories."

Before Miss Vale left she had implored him to do all he could to clear
the matter up, for her sake and for Morris's. "Of course," she said in
conclusion, "I now understand that the entire matter will get into the
papers. It is too late to prevent that. But it is not too late for you
to fix the guilt where it belongs. And I have every confidence that
you will do it. If I had not," and her voice quavered pitifully, "I
don't know what I should do."

"I will do what I can. Success sometimes comes easily--sometimes one
is forced to fight hard for it. But rest assured that I will do what I
can."

She was going; he held the library door open for her while the
grave-faced Stumph waited in the hall.

"It will, perhaps, be necessary for me to see Mr. Morris sometime
during the course of the day,"