Suspense is a state of tension and uncertainty.
The setting of the story, the deep south during the Great Depression, is very important to the story. Race relations hadn't changed a great deal from the 1930's to the late 1950's when Harper Lee wrote the novel, so she could write about a past time from a view into her current time. Blacks in the south were segregated as many southerners, like many people, did things the way their parents and grandparents did them and thought the way their parents and grandparents thought. In the 1930's, the Civil War was 70 years old, but the grandparents of adults during 1930's would have probably had a clear memory of it. People didn't travel much in the 1930's due to lack of money and lack of opportunity. People were much more provincial then than they are now because, in part, we have mass media and easy access to travel. That provincialism helped maintain the views of southerners from the Civil War through the 1930's and beyond. All of that information makes it easier to understand why some of the characters in the story acted the way they did, particularly the uneducated ones. The jury in the Tom Robinson trial was made up mostly of farmers who would have had a very limited education, so their prejudices ran deep. That doesn't excuse what they did, but it does help explain it. If the story had been set in a more modern time after the Civil Rights movement, there would have been less chance of a guilty verdict, no matter where the story was set. Also important to the story's setting is the fact that the story does take place in the rural south. These people were greatly and negatively affected by the Great Depression. Many of the small farmers, like the Cunninghams, couldn't make ends meet with what was grown on their farms. They were angry and bitter and sometimes that anger came out at any convenient source such as when the group of farmers planned to lynch Tom at the jail. The setting was essential to the story so that the reader could see how ignorance bred prejudice and enlightenment banished it.
