The In Crowd (2000 film)

The In Crowd is a 2000 teen thriller film directed by Mary Lambert and stars Susan Ward, Lori Heuring, Matthew Settle and Nathan Baxton.

Brittany, a young woman who lives in the area, befriends Adrien and takes her under her wing, accepting her as part of a clique of wealthy teenagers. Brittanys group of friends make comments about how much Adrien looks like Brittanys older sister who had moved away. At first she enjoys being a close confidant of Brittany but Adrien soon begins to discover how twisted Brittany actually is when Matt Curtis, an object of Brittanys affection begins to show an interest in Adrien.Brittany sets out to get rid of Adrien, by stealing her file from Henrys office and discovers Adriens past. Adriens revelation of Brittany is much more disturbing, when she discovers that Brittanys older sister used to be queen bee of this circle of friends and that Brittany was often treated badly by her older sister. Brittany is furious that her best friend Kelly deceived her when she overhears her explaining the situation of her missing sister to Adrien. To keep her secret under wraps, she kills Kelly and later kills Henry, pinning the blame on Adrien. Her supervisor knew about Adriens stay at the mental institution and readily believed Adrien to be the killer. ........

Source: Wikipedia