Because he did not want any more trouble in Maycomb pertaining to Tom Robinson's case. He knew that it was improbable that Jem could have killed him, considering he is half of Bob Ewell's size and had just broken his arm. Although it could be inferred Boo killed him, he did not want to trouble him, because he didn't do anything wrong. He saved the kids, and did the town a favor.
Because its true...
Heck Tate insisted that Bob Ewell fell on his own knife to protect Boo Radley from having to face the consequences of killing Bob to save Scout and Jem. He believed that it was better to keep Boo's involvement a secret to preserve his privacy and peace.
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.
He decided to tell the town that Bob Ewell fell on his own knife and killed himself, to protect Boo Radley from unwanted attention and scrutiny. Heck Tate believed it was the best outcome for all involved.
Heck Tate asks Atticus to leave the room after hearing about Bob Ewell's death in the book "To Kill a Mockingbird." Heck Tate insists that Bob Ewell fell on his own knife and that Boo Radley should not be brought into the public eye.
Have you not read the book AT ALL?He says that he fell on his own knife and killed himself."Mr. Finch," Mr. Tate said stolidly, "Bob Ewell fell on his knife. He killed himself."- Chapter 30
Sheriff Tate insists that Bob Ewell accidentally fell on his own knife and it was self-inflicted, as he tries to protect the innocence and bravery of Boo Radley. He doesn't want Boo to face unwanted attention or consequences for saving Scout and Jem.
Mr. Heck Tate find Bob Ewell dead under the tree with a knife in him.
By saying that Bob Ewell fell on his own knife, Heck Tate is protecting Arthur (Boo) Radley from the unwanted attention of the town. He knows Boo only intended to protect Jem and Scout, and that he is a shy, kind man. Boo would be very uncomfortable if attention was drawn to his actions. As Scout says, it would be like killing a mockingbird, for it would bring pain to a kind-hearted man who only wants to help others.
Heck Tate determines that Bob Ewell fell on his own knife to protect the innocence of Boo Radley, who actually killed Ewell in defense of Scout and Jem. Tate knows that Boo would be unfairly scrutinized and possibly face legal repercussions if the truth came out, so he chooses to frame the incident as an accidental death to spare Boo from the spotlight. This decision reflects the theme of justice and morality in Harper Lee's novel "To Kill a Mockingbird."
Boo Radley killed Bob Ewell because Bob was trying to kill Jem and Scout. At first, Atticus believes Jem did it. Heck Tate insists that they claim Bob Ewell fell on his knife. Atticus thinks Heck is protecting Jem and he does not want to cover up what he thinks happened. When he finally understands that Boo did it he agrees to the lie.
In "To Kill a Mockingbird," the sheriff, Heck Tate, reveals that he found the switchblade that Bob Ewell used in the attack on Scout and Jem near the Ewell house after the incident. Heck Tate states that Bob Ewell fell on his knife during the struggle, leading to his own demise.