Heck Tate, The Sheriff shared that Mayella Ewell was beaten all on the right side of her body.
Atticus proved that, since his left arm is useless, Tom Robinson could not have raped or killed Mayella. In a farming accident when he was a child, his left arm was hurt. If the bruise is on Mayella's right eye, she would have been struck by the person who hit her with their left hand. Tom is unable to use his left hand. He also shows later that Bob Ewell, Mayella's dad, is left handed, so he could have beaten Mayella when he saw her trying to kiss a black man, Tom Robinson.
