The most compelling evidence that supports Tom's innocence relies on Mayella Ewell's testimony. She claims that Tom assaulted her and "had [her] round the neck" so that she couldn't escape. Heck Tate verifies that there were finger marks all around her neck. Yet when Mayella is asked to point out her assailant in the courtroom and Tom stands, his left arm is at least a foot shorter than his right. His hand is small and shriveled, and he isn't able to use this arm; therefore, Tom could not have inflicted the bruises around Mayella's neck—or the bruising on her face.
Tom's character is also of great importance when considering the claims. Although he must have known that visiting a white woman's residence alone during this time and in this setting was dangerous, Tom's sense of moral decency caused him to reach out and try to help her, anyway. Tom testifies that Mayella frequently asked him in to help her do odd chores, and he refused payment for his services because he "knowed she didn't have no nickels to spare." Tom did anything Mayella asked him for help with, from carrying water to chopping firewood for her. He testifies that he never stepped onto the Ewell property without being asked by Mayella, and that on the day in question, it was Mayella who kissed Tom—by surprise. Tom realized the inherent danger in this situation and tried to make an escape as quickly as possible. But it was too late; Mayella's father had seen what had happened through the window and had screamed that he would kill her.
Therefore, it is also crucial to examine the motive and character of Bob Ewell in examining Tom's innocence. Tom testifies that when he left, Bob was threatening Mayella, and that only one chair in the entire room was disturbed at that point. However, Mayella certainly did receive various injuries by a man who led with his left fist, and Bob proves that he is left-handed. Bob himself corroborates the testimony of Heck Tate, verifying that "her [right] eye was blacked and she was mighty beat up." Bob presents conflicting testimony and acknowledges that despite Mayella's injuries, he never considered calling for a doctor. His testimony presents his clearly racist views; at one point, he asserts that Black people are "dangerous to live around" and devalue his property.
The testimonies of Mayella Ewell, Tom Robinson, and Bob Ewell present clear evidence that it was Bob Ewell who attacked Mayella in an angry rage—not Tom Robinson.