One way in which Lee heightens tension in the scene is juxtaposing the approach of the prosecuting council, Mr. Gilmer and that of Atticus. While Mr. Gilmer "leads" the witness, Mayella, by saying things like, "You fought him off as hard as you could? Fought him tooth and nail?" Atticus slowly lets Mayella's character speak for itself. He asks her seemingly innocent questions about her life with her impoverished family, her friends, and especially the way her father treats her.
"Do you love your father, Miss Mayella?"
As she stammers over her response, Atticus gently asks if the man beats her. Though she responds negatively, it is clear that her life at home is hellish.
This gentle prodding allows Atticus to get to the lie Mayella has been compelled to tell about Tom. He asks again and again in his gentle way for details. When she claims that Tom "hit her and choked her," Atticus proves that this could not have been the case. Tom had suffered an accident that leaves his left arm useless.
Mayella's appearance alone sets her apart from the rest of her family. The reader feels suspense concerning how she'll be different from the others. Could she really be a victim?
After reading about her pathetic home and personal life, the reader also can't wait to hear what Tom has to say. Once again, Lee uses character description to build suspense. But this time it includes her home life, not just her appearance.
Lee's most powerful use of suspense is through Atticus. His pounding questions-- why the children didn't come running, why she didn't put up a better fight, how could Tom have beaten her with a non-functioning hand--all create the greatest suspense in this chapter.