What evidence is given that Tom Robinson is actually, categorically innocent of the crime for which he is charged in To Kill a Mockingbird?
The reader is never given absolute evidence that Tom Robinson is innocent of raping Mayella Ewell. Instead, the reader must decide between the questionable testimony of the Ewells and the seemingly believable version of events told by Tom. For the Maycomb jury, and for most of the townspeople, it is an easy choice: In Depression era Alabama of the 1930s, a white man's word is always taken--even if it is a lowlife like Bob Ewell--over the word of a black man. For the average unbiased reader, Tom is a far more believable witness, and it probably seems obvious that Bob's and Mayella's stories don't quite mesh. As for evidence, the only witnesses to the supposed attack were Bob and Mayella, and Sheriff Tate has taken Bob's version of the event as the basis for the official charges. Mayella was never treated by a doctor, and there is no medical evidence that a rape ever occurred. Mayella was unable to give specific testimony about the sexual attack, and the bruises she did receive appeared to show that they were caused by a left-handed man with two good arms. Tom's left arm is crippled, while it is shown that Bob is left-handed. Tom also testifies that Mayella's father saw her hug Tom and then heard Bob call Mayella a "whore" and threaten to kill her. Tom claims that it was Mayella who attacked him, and that he ran away immediately afterward. Tom knew he was innocent of the charges, but fleeing made him appear guilty. He had been frightened, and he told Atticus that
"... if you was a nigger like me, you'd be scared, too. (Chapter 19)