I'm Not Who You Think I Am - Peg Kehret

Ginger Shaw first saw the odd woman following her during a party. Then the strange phone calls start and the woman confronts Ginger. She claims to hold a secret from the past. But when the confrontation turns violent and the woman's idle threats turn deadly, Ginger is forced into a crisis of loyalty and honor. Who is the strange woman in the white car watching Ginger? She appears at Ginger's birthday party, at her school, and in front of her house, but Ginger has never met her before. When she confronts Ginger, she reveals a secret that will change Ginger's life. And when the woman's confrontations become threatening, Ginger is forced into a crisis of loyalty and honor--a crisis from which her family might never recover.