A Sister's Nightmare (TV)

Sibling rivalry returns to torment Jane, a young police officer, after her older sister Cass is released from the state hospital for the criminally insane. Cass begins showing an increasing interest in getting back her daughter whom Jane has been raising. Unable to convince others her sister is still dangerous, and wanting to protect her niece, the young police officer takes matters into her own hands and goes after her sister herself. - IMDb