Insane(1984)

Fernando (Ace Vergel), a homicidal killer with a bent childhood is quickly sought out by the police. In hiding, he poses as a bus driver for an all girls high school, as they make their way to a retreat for relaxation and self discovery. The murderer raises the body count with the class' fodder, while keeping his 'protective' eyes singled on Chiqui (Snooky Serna).