The Babysitter and the Man Upstairs
This is a very popular urban legend. A babysitter receives a call from an anonymous person who says “Have you checked the children?”. The man on the phone sometimes said that he has killed the children and plans to attack the babysitter too. Scared, the babysitter calls the cops who advise her to keep the guy on the phone so they can trace the call. The police then telephone her saying to get out of the house. She runs out of the house and a policeman outside informs her that the calls had been traced to a telephone extension upstairs in the house, having murdered the children and planning to attack the babysitter.
The movie When A Stranger Calls is based loosely on this urban legend.
(Source: Brunvand, Jan. Encyclopedia of Urban Legends. 2001.)
