“Oh, she got in, all right. Waring let her in, at the French window. Probably that’s when he locked his door. But—say she killed him—how did she get out and lock the room behind her?”

“She couldn’t. The window locks are bolts, and could not be shot from outside. For the moment I see no explanation. It is blank, utter mystery. When can I see Miss Austin?”

“Too late tonight, tomorrow morning will have to do. But she won’t run away. The police won’t let her.”

“Yet they can’t hold her.”

“They are doing so. They claim she was the last one to see the victim alive—”

“Does she admit that?”

“Not she! She admits nothing. You’ll get nothing out of that little Sphinx!”

“All right, then, Mr. Trask, if you’ve finished your tale, suppose you leave me here to ruminate over this thing, and I’ll go up to my room when I wish.”

Trask went off to bed, and Stone and his young assistant sat and looked at each other.

“Up against it, F. Stone?”