I'll Be Seeing You (2004)

When a woman is murdered and when she is found the police assume she's Patricia Collins. But when they call her home to tell her mother, she answers so they ask her to come see the woman and is shocked to see she looks like her. And it appears she was on her way to see Patricia. Patricia learns that the woman is her half sister and she was coming to see her about their father who disappeared some time ago. So she thinks that the person who was responsible for her father's disappearance was the one who killed her to keep her from telling Patricia what she knows.