One of the final links between the Edgar Wallace-based German krimi genre and the Italian giallo thriller, this creepy mystery stars Fabio Testi as a college professor who sleeps with his students and is blamed when a string of murders occurs. Joachim Fuchsberger, as usual, is the police inspector trying to solve the killings; Camille Keaton, Buster Keaton's grand-niece and later the star of Meir Zarchi's I Spit on Your Grave (1980) has a supporting role; cameraman Aristide Massaccesi, later infamous as gore director Joe D'Amato, turns up as a cop. Massimo Dallamano's direction is assured. This first-rate thriller was based on Wallace's Secret of the Green Pin.~ Robert Firsching, All Movie Guide