All Around The Town by Mary Higgins Clark
When Professor Allan Grant is found stabbed to death, all the evidence points to an obsessed student, 21-year-old Laurie Kenyon. She sent him passionate letters, stalked him, watched him through his study window. And after the murder, she wakes up in her dormitory, covered in blood and clutching the knife that killed him, with no memory of the brutal crime.
Laurie's sister and attorney, Sarah, is the only one who understands Laurie's daily nightmare and the shocking lingering effects of a childhood kidnapping too hideous to be recalled. Laurie's abductors - Bic Hawkins and his wife Opal, now prominent TV evangelists - fear she will start to remember her life with them. They must ensure that her past remains buried at all costs, even if it means Bic has to carry out the murderous threat he made all those years ago to a terrified girl...