Chapter 29-31

At the sheriff's request, Scout recounts what happened, realizing that one of the strange noises she heard was Jem's arm breaking. The sheriff notices knife marks on Scout's costume, and she understands that Bob Ewell had intended to kill her and Jem. She also recognizes that the stranger — the man who pulled Ewell off of her and saved both children's lives — is Boo Radley.
Scout, Atticus, Heck Tate, and Boo retire to the front porch. Atticus begins defending Jem, insisting that killing Bob Ewell was clearly self-defense. Sheriff Tate corrects Atticus, saying that Bob Ewell fell on his own knife. Atticus appreciates what Heck is trying to do, but he doesn't want anyone to cover for Jem. The sheriff remains adamant, saying that he isn't protecting Jem. As the men argue, Atticus realizes that Boo Radley killed Ewell, and it is Boo who Tate is trying to protect. They finally agree that Ewell did fall on his own knife, a decision Scout fully understands.
Boo sees Jem one more time and then asks Scout to take him home. Scout allows him to escort her to his door. She returns to Jem's room and Atticus reads aloud to her until she falls asleep. He tucks her in her own bed, and then retreats to Jem's room, where he spends the night.