"A Friend To Die For," also known as "Death Of A Cheerleader," is a true-story movie based on the murder of Kirsten Costas and Bernadette Protti. The "teen murders classmate" movie premiered in 1994 as a Monday night-NBC movie of the week. The names were changed to Stacy Lockwood and Angela Delvecchio in the movie.
"Death Of A Cheerleader" is about a group of teens living in an affluent school district, where being beautiful and rich is important. Stacy Lockwood is a popular cheerleader who makes fun of girls who are less rich and less popular. Angela Delvecchio envies Stacy so much that she is willing to do anything just to be friends with her. Delvecchio seems to be making her way up the popularity ranks, until a brutal attack leaves one of them dead.
According to The Movies Based On True Stories Database, the real story that inspired "A Friend To Die For" happened in California in 1984, when a popular cheerleader was stabbed to death by her classmate. Police say, Bernadette Protti stabbed her classmate Kirsten Costas one night in the upscale neighborhood of Orinda, after luring Costas out of the house by inviting her to a party.
According to court records, once Costas learned that there was no party and that it was actually Bernadette Protti who had made the phone call, Kirsten Costas became upset and an altercation ensued which ended in Costas' violent death.
The murder was unsolved for several months until Protti finally confessed to the murder. Bernadette Protti served time in prison until 1992. When she was released, she changed her name and created a new identity.
The movie based on her case now airs on Lifetime Movie Network. The case has also been the subject of a few documentaries based on teen murders.