Why did Heck Tate insist that Bob Ewells fell on his own knife?

Heck Tate insisted that Bob Ewell fell on his own knife in Harper Lee's "To Kill a Mockingbird" to protect Boo Radley from being thrust into the public eye and potentially facing legal repercussions. Tate believed that Boo acted in self-defense to save the children, Scout and Jem, from Bob Ewell's attack. By attributing Bob Ewell's death to his own actions, Tate sought to preserve Boo's privacy and prevent him from being hailed as a hero or subjected to unwanted attention.