Scout mentions that there were three events that seemed out of the ordinary that happened in October and involved Bob Ewell. The first thing that happened involved Bob Ewell losing his job at the WPA for laziness and blaming Atticus for getting him fired. The second thing that happened involved Judge Taylor hearing someone attempt to sneak into his house on a Sunday night. Although he did not identity Bob Ewell as the culprit, it is implied that Bob was the intruder at the back door and fled before Judge Taylor saw him. The third thing that happened involved Bob Ewell threatening Helen Robinson on her walk to work. Bob ended up following her at a distance while cursing at Helen as she walked to work. All three instances depict Bob Ewell attempting to blame and get revenge on those involved and indirectly involved in the Tom Robinson trial. Bob Ewell was clearly embarrassed when Atticus revealed the truth during the trial and attempts to get revenge on those who supported Atticus. Bob Ewell's apparently harmless actions reveal his cowardice and bitterness towards Atticus and his supporters. Bob's attempts to disturb Judge Taylor, intimidate Helen Robinson, and blame Atticus for getting him fired are his way of expressing his bitterness regarding the outcome of the trial.

In Chapter 27, someone also breaks into Judge Taylor's house. Because Bob Ewell is so upset and embarrassed, we can assume that he is to blame. Additionally, the Ewell family is caught throwing rocks at Helen Robinson as she walks to work. Mr. Deas threatens Bob when this occurs, spurring Bob Ewell's anger even further.

Last sentence in the chapter:  "Mr. Bob Ewell stopped Atticus on the post office corner, spat in his face, and told him he'd get him if it took the rest of his life."  Spitting in the face is an insult; it was meant to show Ewell's contempt for him. From Ewell's point of view, Atticus insulted him but implying Ewell, not Tom, assaulted Mayella.  The subsequent threat proves true at the end of the novel when Ewell attacks Scout and Jem while walking home in the dark.