Answer: The author characterizes Tom as a decent and innocent man, while the Ewells have deep racial prejudices against him.
Step-by-step explanation:
In Harper Lee's novel, "To Kill a Mockingbird" (1960), Tom Robinson is an innocent man who has been falsely accused of a crime just because he is black.
Lee characterizes Tom as innocent and morally-upright, which is primarily embodied in the fact that Atticus strongly believes in his innocence and gives his best to defend him. Atticus describes him in the following way:
"He’s a member of Calpurnia’s church, and Cal knows his family well. She says they’re clean living folks."
During the trial, multiple proofs are given that show that Tom is indeed innocent. For instance, he cannot use his left hand, and he could not have held Ewell's daughter down by using only one hand.
Bob Ewell, however, driven by racial prejudices that he has, believes that Tom does not deserve to live as a free man and directly accuses him during the trial:
"I seen that black ni***r yonder ruttin' on my Mayella!"