In Chapter 15, Lee begins to create tension as the build up to the court case begins. Harper Lee uses what we know already about Maycomb and its residents and twists it into a situation we may not have been expecting. For example, when Scout thinks that the group of men that are surrounding Atticus at Maycomb jail that night are the same men that arrived at her house previously in the novel. The way in which Lee decides to present the gangs makes us, the reader, also believe that these are the same people. However it is soon made clear when Scout runs into the crowd and realises that they are a completely different group of people.
In Chapter 18, as the trial continues Mayella begins to give her evidence. Lee makes us feel sorry for her, as she is presented as being very frightened and very immature for her age. Lee creates tension in this part of the trial by giving false hope to the reader. As Atticus picks apart the case it makes the reader feel as if Tom Robinson may actually win the case.
At this point Atticus builds up his own case: Mayella was not raped but beaten by Bob Ewell, her own father. He does this by noticing that Mayella was injured on the right side of her body - something Tom Robinson would not have been able to do as his left hand was injured in an accident and he is no longer able to use it.
