The Babysitter (1980)

Overprotective mother Liz Benedict meets 18yearold orphan Joanna Redwine and hires her as house help and livein companion to rambunctious daughter Tara Lizs husband Jeff isnt too thrilled with the arrangement and his fears soon prove justified when Joanna begins to manipulate everyone and to slowly destroy the family Meanwhile nextdoor neighbor Dr Linquist investigates and discovers Joanna has a disturbing past