The Bad Seed (1985)

Rachel Penmark is a 9-year-old girl who looks the picture of perfection but is really a cold-blooded killer. Several disturbing recent incidents have led Rachel's mother Christine to suspect that her daughter was responsible for them. Christine also has recurring memories of her mother searching for her. Christine's adoptive father tells her about her biological mother, who was a convicted killer, and Christine is convinced that Rachel inherited her grandmother's madness.