It's too bad that Arthur Radley does not talk because it would have been very interesting to hear exactly how he saved Jem and Scout from the clutches of evil Bob Ewell. However, Scout's limited view of the scene due to her ham costume certainly add suspense and mystery to the telling of it. With Jem laid up with a broken elbow, and asleep with the help from the doctor, Sheriff Heck Tate had to decide what happened based on evidence from the scene and Scout's recollections. Ironically, it's Jem's own father, Atticus, who concludes that Jem must have stabbed Bob Ewell in defense of his sister. Luckily, the Sheriff considers things differently as follows:
"'You hear what Scout said, there's not doubt about it. She said Jem got up and yanked him off her--he probably got hold of Ewell's knife somehow in the dark. . . we'll find out tomorrow.'
'Mis-ter Finch, hold on,' said Mr. Tate. 'Jem never stabbed Bob Ewell'" (272).
The discussion goes on, but the decision to prosecute comes down to Sheriff Tate's decision on the matter. Granted, Tate goes further to change the crime scene's narrative to safe-guard Boo Radley, but either way, Jem is innocent. Sheriff Tate solidifies his decision by saying the following:
"For once, if you don't see it my way, there's not much you can do about it. If you wanta try I'll call you a liar to your face. Your boy never stabbed Bob Ewell. . . didn't come near a mile of it and now you know it. All he wanted to do was get him and his sister safely home" (275).