There are several characters that pass away throughout the course of the novel. Scout recalls the uneventful deaths of Mr. and Mrs. Radley. Scout and Jem were both upset to learn that Boo Radley had not killed his parents. In Chapter 11, Mrs. Dubose, their racist neighbor, also dies throughout the course of the novel. She was a morphine addict who died from a chronic disease. Tom Robinson, Atticus' African American client, also dies. After becoming a victim of racial injustice, Tom attempts to escape from prison and is shot by the guards numerous times. After Tom dies, Bob Ewell passes away after Boo Radley stabs him while Boo is defending Jem and Scout. Bob Ewell tried to kill Jem and Scout following the Maycomb Halloween festival and Boo Radley killed Bob in self-defense.
The main characters who die are Tom Robinson, Mrs. Dubose, and Bob Ewell. Tom's death is the symbolic killing of a mockingbird. Tom is innocent, but is convicted due to the prejudice of people. It is on his way to jail, that, out of desperation, Tom breaks free and tries to run, then is shot. Mrs. Dubose's death symbolizes the strength of will and persistence it takes to fight even when one knows he will lose anyway - just like Atticus knew he'd lose his case and Tom would get convicted by the jury in Maycomb. Bob Ewell's death is further proof of the type of desperate, despicable person that he is. He was killed trying to harm Scout and Jem. This is where Boo saves the children's lives by killing Ewell which, again, helps to emphasize the idea that mockingirds (Boo, in this case) do no harm, they only "sing their hearts out for us".