In Chapter 27 of Harper Lee's novel To Kill a Mockingbird, the novel's quintessential depiction of 'poor white trash,' Bob Ewell, is stalking the wife of Tom Robinson, the African American framed for raping Ewell's daughter, Mayella. Ewell has already been portrayed as the novel's most nefarious antagonist of the morally-upstanding Finch family, and was directly responsible for Tom's imprisonment and subsequent death. Lee continues to portray this heinous individual in the most threatening light, describing his menacing stalking of Helen Robinson:
"Helen went to work next morning and used the public road. Nobody chunked at her, but when she was a few yards beyond the Ewell house, she looked around and saw Mr. Ewell walking behind her. She turned and walked on, and Mr. Ewell kept the same distance behind her until she reached Mr. Link Deas’s house. All the way to the house, Helen said, she heard a soft voice behind her, crooning foul words."
Lee has set the stage for the inevitable climactic scene between good and evil, with Bob Ewell representing the latter. In Chapter 28, he receives the punishment he is due, albeit from an unexpected source. A mysterious figure has attacked Jem and Scout in the darkness of night, but the children are able to escape to their home when a scuffle ensues. Later, safely at home with their father, Heck Tate arrives with a message:
Mr. Tate found his neck and rubbed it. “Bob Ewell’s lyin‘ on the ground under that tree down yonder with a kitchen knife stuck up under his ribs. He’s dead, Mr. Finch.”
In the subsequent chapters, it is revealed that Jem and Scout's savior was none other than the mysterious figure of Boo Radley, and the children are, for the first time, exposed to this insulated but benevolent man. Seeing the Finch children attacked by Bob Ewell, Boo has come to their rescue and, in the process, Ewell was somehow stabbed to death with his own knife. Atticus's suspicion that Jem had stabbed Ewell is barely allayed, but he is convinced by the town's chief law enforcement officer, Heck Tate, to let the matter rest, with Jem and the rest of Maycomb's population content to accept the story that the dead bigot was impaled on his own knife when he fell to the ground after being pulled off of the children. Tate justifies this approach to justice by referencing the clearly-innocent Tom Robinson's death, noting:
"There’s a black boy dead for no reason, and the man responsible for it’s dead. Let the dead bury the dead this time, Mr. Finch. Let the dead bury the dead.”
Bob Ewell dies by his own knife, and the exact circumstances remain a mystery. What isn't a mystery, however, is that Boo Radley emerged from his isolation to save the children from a violent, spiteful drunk.