The single most vile character in Harper Lee's coming-of-age-in-the-Deep-South novel, To Kill a Mockingbird, is Robert E. Lee "Bob" Ewell, a poor white man whose virulently racist views propel the story's narrative. While Lee's novel is about Scout and Jem and Atticus Finch, and involves the former's reminisces about her childhood in Maycomb, Alabama, the underlying theme of endemic racism and the victimization of a crippled desperately poor African American man wrongly accused of raping Ewell's daughter all emanate from the warped mind of Bob Ewell.
Identifying Bob Ewell from the clues provided in the student's question is relatively simple. The following passages from To Kill a Mockingbird all point directly at this particular character:
"Maycomb’s Ewells lived behind the town garbage dump in what was once a Negro cabin."
"Nobody was quite sure how many children were on the place. Some people said six, others said nine; there were always several dirty-faced ones at the windows when anyone passed by."
“Mr. Ewell?” My memory stirred. “Does he have anything to do with those Ewells that come every first day of school an‘ then go home? Why, Atticus said they were absolute trash—I never heard Atticus talk about folks the way he talked about the Ewells.
So, the character about whom the student is inquiring is Bob Ewell. Ewell's shortcomings as a human being are evident throughout the novel, but it is during the trial of Tom Robinson, the aforementioned wrongly-accused, wrongly-convicted, and tragically-killed African American man that the full measure of Ewell's character are revealed. Sheriff Heck Tate's description of Ewell's daughter Mayella immediately following the alleged assault is telling. Testifying in Tom's trial for rape, the sheriff describes a badly bruised young woman with a black eye -- injuries, it will be revealed, that could not have come from the crippled defendant, but that which clearly were inflicted by her father. Ewelll is, in every sense, white trash, and his unfounded accusation against Tom Robinson, including in his perjurious testimony during Tom's trial for rape, underscored the depths to which this sorry individual will descend to advance his racist agenda.