Sex, Demons and Death (1975) Salvatore Bugnatelli

Marcello (Gabriele Tinti) and Micaela (Magda Konopka) want to have a child, but it seems Micaela has medical issues preventing a pregnancy. Marcello wants to go to Switzerland for more exotic treatments, but Micaela chooses instead to have her niece Letizia (Franca Gonella) brought home from a fancy boarding school to live with them instead (Letizia's mother/Micaela's sister is dead). Unfortunately for Marcello and Micaela, there is something wrong with Letizia, whose presence in their home kicks off a sinister series of disturbing events.