Unhinged (2006)

Unhinged tells the story of Karen, a forensics student who has just found out her best friend from high school has been brutally murdered. While her boyfriend David attends college in another town, Karen decides to rekindle her relationships with her other friends from high school, including her ex-boyfriend Chris. Soon, the others become victims of the same serial murderer and it falls to Karen and Chris to try to stop the murders before they themselves become victims.