"Lost Youth" is not merely a sociological study of the post-war crime rise in Italy among the young middle-class, it is also a study of how family and friends can be completely blind to a sociopathic killer in their midst. The then new young actor Jacques Sernas (forever under-rated thereafter) garnered deserved critical praise for his chilling portrayal of the young 20 yr old criminal pursuing his agenda with enough sang-froid to freeze Europe. The bleak story gets a slight lift from young Massimo Girotti's performance as a tyro police inspector who unfortunately becomes involved with the sister of the perpetrator he is seeking. The black and white cinematography is pure classic noir cinema.