Chainsaw Sally (2004)

Sally is a young woman living two lives: a calmly librarian by day, and a brutal serial killer by night where she randomly targets any man or woman whom even slightly upsets her. Sally lives with her reclusive, transvestite younger brother Rudy whom assists her with the killings. Both Sally and Ruby were traumatized as children when both of them witnessed three lunatics murder their mother and father before they, with 'Daddy's' help, killed the three murderous psychos.