When Bob Ewell testifies, he says that he heard Mayella screaming and came up to the window to see Tom Robinson raping her.
Well, Mayella was raisin' this holy racket so I dropped m'load and run as fast as I could but I run into th' fence, but when I got distangled I run up to th' window and I seen-" ... He stood up and pointed his finger at Tom Robinson…(ch 17)
He then claimed he ran into the house to find Mayella on the ground, and could not run after Tom Robinson. Instead he called Heck Tate.
Mayella claimed she was on the porch and Tom Robinson passed, and she asked him to bust up a piece of furniture.
So he come in the yard an' I went in the house to get him the nickel and I turned around an 'fore I knew it he was on me. Just run up behind me, he did. (ch 18)
She them claimed when her father came in she fainted.
When Atticus cross-examines her, Mayella gets confused.
"No, I don't recollect if he hit me. I mean yes I do, he hit me." (ch 18)
Mayella does her best to confirm her father’s testimony, but she gets the lies a little mixed up. In the end, it is obvious that Tom Robinson could not have done it.
Mayella is a young girl in a bad situation. She tries to follow her father’s lead and accuse Tom Robinson, but Atticus confuses her and mixes her up. Despite the fact that nothing happened, Robinson is still convicted because he admits he felt sorry for Mayella, and a black man cannot feel sorry for a white woman in Maycomb in the 1930s.