How did the author of to kill a mockingbird use the description of settings and events immediately prior to the trial build a mood of suspense?

The town is filled with the gossip of its residents and curious outsiders. The perimeter of the courthouse is filled with familes having picnics, as if they're at a fair or celebration, rather than a trial determining someone's future. If I could call it anything, I'd call it a circus..... the players were performing for the crown, and the crowd stood in anticipation of something that was already expected.