This is interesting giallo-style Italian thriller similar to the later horror masterpiece Suspiria but without the supernatural elements, and the schoolgirl giallo What Have You Done to Solange? but with less sleaze (in fact, it seemed like the edited version shown in the US didn't even have any nudity in it). It's very hard to find these days, but worth finding. It's a very seminal film if nothing else. The first bathtub murder was borrowed verbatim for the murder of the Cristine Galbo character in Solange. I'm pretty sure the morbid joke of the killer keeping the first body around right under the nose of the later victims inspired Black Christmas, which in turn inspired Halloween, and after that the deluge. (In fact, much of the later US slasher subgenre could easily be traced to two Italian films--this one and Mario Bava's Twitch of the Death Nerve). And certainly no one can deny the influence on Suspiria. While it probably wasn't the first horror movie/thriller to be set in a girl's school or girl's dormitory, it might have been the first to fully the exploit the psycho-killer and "Ten Little Indians" possibilities of this creepy setting. If you like this movie(and you speak Spanish), also check out the contemporary Spanish horror/thriller, La Residencia which is very similar.