A black gloved killer strangles an unidentified woman in the bath, stuffs her naked body into a trunk and puts it on the train for the south of France. The next thing we see is the trunk atop the minibus from St Hilda's School for Girls - what is it with St Hilda; didn't the college in What Have You Done to Solange have the same patron saint? - whilst inside some of the exclusive boarding school's staff are introduced to us: Sr Brazi, the new gym teacher; Richard Barrett, the riding teacher, "very popular with the girls"; Misses Martin and Clay and handyman La Foret.
Insert finishing school joke here; I find it interesting that the 's is perhaps missing from St Hilda's - possible coincidental parallels with the fashion house sign in Blood and Black Lace?
As it turns out there about as many of them as pupils, although this staff:student ratio is one that also proves to be in something of a state of flux when it emerges that the still unidentified killer has in fact accompanied his or her luggage.
The first victim is Betty-Ann, who strays where she shouldn't into the storeroom containing the trunk, but is assumed by the headmistress to have run away. Rather than calling in the authorities, she has the staff conduct a search of the grounds, while the students are ordered to stay in their rooms but proceed, inevitably, to sneak out for secret rendezvous and the like.
Compare this to the shower murder in Crimes of the Black Cat - what a difference a few years makes; or Psycho as thriller model and Psycho as slasher model
Betty-Ann is then followed by Cynthia in what could be a case of mistaken identity, insofar as Lucille had entered the showers a few moments before. Faced with a body, the headmistress has no option but to call in the police, while the Nancy Drew style Jill decides to conduct her own investigation. This is a wise move seeing as the chief investigating officer, as played by Michael Rennie in what-am-I-doing-here mode, needs all the help he can get. Suspicion at first falls upon the La Foret, incarnated by the ever-shifty Alan Collins / Luciano Pigozzi in sweaty peeping tom mode, but then he too gets offed...
Margheriti's direction is comparatively restrained, his mise-en-scene more classical than flashy pop modernist. There's a calculated elegance to his compositions and camera movements that evinces a professional very much in control of his medium at work.
A similar of restraint carries through into the depictions of sex and violence, with as much suggested as shown and a sense of decorum prevailing as far as shower scenes and burgeoning schoolgirl sexuality are concerned. (Silvia Dioniso plays one of the schoolgirls, but not such that you'd see her as a forerunner of Waves of Lust as the like.)
The male voyeur becomes the subject of the female gaze; note that Jill is not punished for this usurpation of a purportedly masculine prerogative
Genre scholars will no doubt want to compare and contrast with Solange, released a mere four years later, in this regard - especially since our Schoolgirl Killer, whose identity is probably the film's biggest surprise, proves to have a financial rather than psychosexual or revenge motivation, although disappointingly we don't really have the opportunity to solve the case for ourselves.
More post-Blood and Black Lace, pre-Bird with the Crystal Plumage black glove as metonymic killer stand (hand?) in
Likewise, the involvement of Mario Bava in writing the story cannot but lead to imagining what might have been in terms of a school set version of Blood and Black Lace, perhaps as riposte to the Kriminal installment Omicidio al riformatorio that had in turn riffed on his film within the context of a reform school (cf. http://www.horschamp.qc.ca/new_offscreen/fumetti.html)
Guess what's used to kill Pigozzi...
Lucille tries to persuade another student to double for her, as Margheriti's composition futher makes the point
At any rate, Carlo Savina's bright and breezy score further conveys the sense that nothing here is really to taken that seriously - another highlight in this regard is a figure in a wetsuit trying to drown one of the girls in the school's outdoor swimming pool, the kind of bizarre idea that only makes sense in a context where Brazi is a scuba expert and agues for lessons in it as a vital part of the girls' education - while the theme music, Nightmare, is more likely to raise a smile than induce fear.
Not, then, the kind of giallo to read too much into, but certainly a fun way to spend an hour and a half.