Whats the movie where some guys with wierd masks on kidnap a teacher and her students that end up killing them?

Fortress (1986 HBO Original movie)


starring Rachel Ward, Sean Garlick, Vernon Wells, Elaine Cusick


IMDb synopsis:


An Australian schoolteacher and her students are kidnapped. She and the children fight for their lives and try to escape from their captors. ';Fortress'; explores a shocking concept which shows how easily a borderline between a victim and an attacker can be crossed. The children and the teacher, calm and peaceful by nature, when driven beyond their limits by the kidnappers, eventually respond with a cruelty and fury extending that of their oppressors.


TRIVIA:


The film is loosely based on the 1972 Faraday School kidnapping of a teacher and her class by Edwin John Eastwood and Robert Clyde Boland. Eastwood later escaped from prison and repeated the crime with another teacher and her class in 1977