Cure

Cure is a movie starring Masato Hagiwara, Kôji Yakusho, and Tsuyoshi Ujiki. A frustrated detective deals with the case of several gruesome murders committed by people who have no recollection of what they've done.
A wave of gruesome murders is sweeping Tokyo. The only connection is a bloody X carved into the neck of each of the victims. In each case, the murderer is found near the victim and remembers nothing of the crime. Detective Takabe and psychologist Sakuma are called in to figure out the connection, but their investigation goes nowhere...