"You acknowledge these footmarks were here, Mr. Blackburn?"
"Certainly," Bobby answered. "I saw them myself just before dark. I knew
Howells ridiculously connected them with the murderer."
"You made a good job of it when you trampled, them out," Robinson hazarded.
But it was clear Bobby's amazement had not been lost on him.
"Or," he went on, "this foreigner who advertises himself as your friend!
He was in the court tonight. We know that."
Suddenly he stooped, and Bobby got on his knees beside him. The cylinder of light held in its centre one mark, clear and distinct in the trampled grass, and with a warm gratitude, a swift apprehension, Bobby thought of Katherine. For the mark in the grass had been made by the heel of a woman's shoe.
"Not the foreigner then," Robinson mused, "not yourself, Blackburn, but a woman, a devoted woman. That's something to get after."
"And if she lies, the impression of the heel will give her away," the coroner suggested.
Robinson grinned.
"You'd make a rotten detective, Coroner. Women's heels are cut to a pattern. There are thousands of shoes whose heels would fit this impression. We need the sole for identification, and that she hasn't left us. But she's done one favour. She's advertised herself as a woman, and there are just three women in the house. One of those committed this serious offence, and the inference is obvious."