Anecdotes

The film was re-released in the US in 1980 under the title "Satan's Playthings", with an ad campaign that made it appear that the movie was about three sexy women who worked for the devil. Roger Ebert blew the movie's cover on his Sneak Previews (1975) show when he picked the film as his "Dog of the Week" and told the audience that the film was really the 1971 British slasher flick "Assault".

The building used for the girls' school is the same building that was used for the girls' school in Les Cinglés du camping (1969).

The film's original title was changed for US release to In the Devil's Garden due to the main character saying that the killer in the film looked like the Devil, and also because the Devil was again becoming a popular subject matter in films after the success of L'Exorciste (1973). The film, under the "Devil's Garden" title, is best known for being released along with Au service du diable (1971) under the title "The Devil's Nightmare" as a "Devil Double Feature".

The TV syndicated title, "Tower of Terror", refers to an electrical tower under which the rapes and murders of some of the schoolgirls take place, and was also the setting where the climax of the film takes place.

Producer Peter Rogers also produced "Carry On..." series of light comedy films for the UK audience.

This was the final film of Patricia Driscoll.