"And don't forget, Mr. Vance," he said, without looking up, "about that diagram Ada found in the rear of the hall near the library door. Maybe this person in the shawl was the one who'd dropped it, and was going to the library to look for it, but got scared off when she saw Ada."
"But whoever shot Rex," said Markham, "evidently stole the paper from him, and therefore wouldn't be worrying about it."
"I guess that's right," Heath admitted reluctantly.
"Such speculation is futile," commented Vance. "This affair is too complicated to be untangled by the unravelling of details. We must determine, if possible, who it was that Ada saw that night. Then we'll have opened a main artery of inquiry."
"How are we going to find that out," demanded O'Brien, "when Ada was the only person who saw this woman in Mrs. Greene's shawl?"
"Your question contains the answer, Inspector. We must see Ada again and try to counteract the suggestion of her own fears. When we explain that it couldn't have been her mother, she may recall some other point that will put us on the right track."
And this was the course taken. When the conference ended, O'Brien departed, and the rest of us dined at the club. At half past eight we were on our way to the Greene mansion.
We found Ada and the cook alone in the drawing-room. The girl sat before the fire, a copy of Grimm's "Fairy-Tales" turned face down on her knees; and Mrs. Mannheim, busy with a lapful of mending, occupied a straight chair near the door.
