Black Christmas (2006)

Billy, a young boy, was abused by his mother as a child. His mother cheated on Billy's father, and eventually killed the man, while keeping Billy in the attic--for good, while she was with her lover and starting a "new" family. As Billy's mother fell pregnant with a daughter and treated her with the love he had never experienced, Billy came out of the attic after years and brutally murdered his mother and her lover. Cut to present day, a group of six sorority sisters consisting of Kelli, Dana, Lauren, Megan, Heather, Melissa and their house mother, who now live in Billy's childhood home, find themselves being harassed by threatening and intimidating mystery phone calls during Christmas Break. As one of the girls goes missing, they begin being murdered one by one by no other than Billy.