What is the theme in The Other Side of Dark by Joan Lowery Nixon?

Fear is certainly a theme in the story. After waking from her coma and learning the circumstances that caused it, Stacy must deal with the fear that accompanies her realization that Mom's murderer may come after her after Brandi Mayer publishes an article claiming Stacy can identify the killer. Stacy is terrified when Monty tries to make her talk to a reporter at the back door, suspecting the man is not really a reporter, especially when he runs from the police. When she returns home, she battles the fear of being left alone, but she is frightened when she sees a shadowy figure in her backyard while babysitting for the neighbors. Soon after, Stacy receives threatening phone calls from a whispery voice, suggesting it would be safer if she forgot about Mom's murderer.