President's Day
(2010)

Mr.Wright (George Stover), a teacher at Lincoln High, is the killer. He had murdered numerous students and faculty members, all done to ensure that Chelsea (Nicolette le Faye) a student he was obsessed with, won the Class Presidency, believing it would be the first step for a bright future for her. Wright reveals this to Chelsea, and even gives her the "gift" of Joanna (Lizzy Denning), a rival of Chelsea, to kill herself.

Chelsea, realizing Mr. Wright is insane and unwilling to actually Joanna, frees her and tries to stab Mr. Wright. Mr. Wright reflexively stabs her mortally with his axe then proceeds to chop her to death. Joanna runs and ignores a police detective who thinks she's the killer. Mr. Wright kills the detective soon after.

Barry (Bennie Mack McCory IV) who had figured out Mr. Wright faked his death and was the killer, finds him and confronts him over killing so many people. With Joanna at his side, they are forced to kill him, first by scalding his face, then decapitating him with his own axe.

The film ends with Barry taking on the role as School president by default, as Mr. Wright had murdered all the other candidates in his killing spree.

Thanks Spectre!