All Around the Town by Mary Higgins Clark

When Laurie Kenyon, a twenty-one-year-old student, is accused of murdering her English professor, she has no memory of the crime. Her fingerprints, however, are everywhere. When she asks her sister, attorney Sarah, to mount her defense, Sarah in turn brings in psychiatrist Justin Donnelly. Kidnapped at the age of four and victimized for two years, Laurie has developed astounding coping skills. Only when the unbearable memories of those lost years are released can the truth of the crime come out—and only then can the final sadistic plan of her abductor, whose obsession is stronger than ever, be revealed.