Bob Ewell was killed by Boo Radley, who stuck a kitchen knife into his chest on the night of Halloween. Bob wanted to get revenge on Atticus for trying to kill the children who were walking back from a Halloween school party.
Susan said: Boo Radley killed Bob Ewell<span> with the </span>knife<span> that Ewell was going to use on Atticus </span>did<span> not want to live a lie protecting Jem from the killing, suggesting </span>he<span> truly If </span>he fell on<span> his </span>knife<span>, it's still possible to roll sideways, over, etc. There's always the possibility Jem killed him, or Bob got </span>stabbed <span>by his own </span>knife<span>.</span>