The Roommate

The Roommate is a 2011 American thriller horror film directed by Christian E. Christiansen and starring Minka Kelly, Leighton Meester, Cam Gigandet, Danneel Harris, Matt Lanter, and Aly Michalka. It was theatrically released on February 4, 2011.

Rebecca attacks Tracy in the shower, pinning her down and ripping out her bellybutton ring, and threatens to kill her unless she stays away from Sara. Tracy moves to another dorm, fearful of Rebecca. An old friend of Saras named Irene Harris, who is a lesbian, invites Sara to move in with her when Saras cat Cuddles is discovered. Rebecca then kills Cuddles by putting her in the dryer. She then lies to Sara that the cat ran away. Rebecca then inflicts injuries upon herself and says she was assaulted by a thug. Sara feels bad for her and decides to spend the Thanksgiving with Rebecca. When Saras philandering fashion design professor, Roberts Zane, kisses her, Rebecca plans to get the professor out of the picture by seducing him while recording their dialogue on a tape recorder to make it sound like he was trying to rape her.During her stay, Sara overhears a conversation between Rebecca and her father Arana, hinting Rebecca has had trouble making friends in the past. Rebeccas mother Fisher mentions that Rebecca is supposed to be taking medication. She and Stephen later find a bottle of Zyprexa pills, used to treat schizophrenia and bipolar disorder. But the bottle is full, implying that Rebecca hasnt been taking the pills. Sara, worried about what would happen, decides to move in with Irene. Irene goes to a club where she sees Rebecca. They make out in the clubs bathroom and Irene, not knowing that Rebecca is Saras roommate, takes Rebecca back to her place. The following morning, Sara goes to Irenes apartment but shes not there. ........

Source: Wikipedia