Female Teacher: In Front of the Students (1982)

Reiko, a young and beautiful teacher, takes a teaching job at an old, run-down high school. The male students in her class are mesmerized by her beauty and become infatuated with her. One night, after tennis practice, she goes to the locker room to change and is viciously assaulted by a man wearing a stocking mask. She discovers that he has left a clue behind: a single piece of a jigsaw puzzle. She sets out to discover who attacked her and why.