The Dark Sea 2006 on netflix

The girlfriend of Detective Luca Mocci moves from the house of her friend Charlotte to live with him. When the corpse of the upper-class escort and student Valentina Martini is found in an apartment, tied and beaten after a kinky sex, Detective Mocci becomes obsessed with his investigation in the underworld of sex in his city, arising dark desires and affecting his relationship with his girlfriend. Written by Claudio Carvalho