"The murderer, after he straightened up from bending over the body, stood completely still for a long moment, there in the shadow. The thud of that tent stake had been so loud that it seemed impossible that no one had heard it. But there was no sound, no movement.
Cautiously now and keeping to the shadow of the sidewall he walked around the penny arcade top to the midway and stood there ready to step out into the light but listening first for footsteps, not wanting to stick his head out to look around. No sound, and he took the step.
And saw Dolly Quintana coming toward him. Wearing moccasins; that accounted for his not having heard her. She stopped and stared at him and the direction of her gaze and now the kinetic sense of something round and heavy in his hand told him the horrible blunder he'd made."
Madball, by Fredric Brown (copyright 1953; quote is from pages 13-14 of the Dell Publishing Company, Inc. Dell First Edition paperback).