The Italian Code of Criminal Procedure contains the rules governing criminal procedure in every court in Italy. The first and initial code in the Italian Republic was established by the Fascist Government in 1930, code adopting an inquisitorial system. In 1988, a new code resulted in a system that could be considered to be somewhere in between the inquisitorial system and the adversarial system.
The main parties to a criminal trial are the judge, the defendant, and the Pubblico Ministero (the prosecutor). There are other parties that are optional, and they are: the Polizia Giudiziaria (Judiciary Police, a branch of the Police whose duty is to help a prosecutor during his investigations), the parte lesa (the injured party), the responsabile civile (civilly liable, who can be compelled to pay damages, if the defendant is not solvent) and the civilmente obbligato per la pena pecuniaria (civilly liable, who can be compelled to pay the fines, if the defendant is not solvent).
The Pubblico Ministero (the public prosecutor) is the one who, during the preliminary investigations, must look for evidence. Since he is a member of the Judiciary (technically, a Magistrato - Magistrate, though not a Giudice[p] - Judge), he must try to find out the truth; that's why he must not only look for evidence that can lead to a conviction, but also that which may lead to an acquittal.
When a Pubblico Ministero or a member of Polizia Giudiziaria becomes aware of the fact that a crime was committed, he must begin his investigation: in Italy, the public prosecutor has the duty to initiate criminal proceedings. The indagato (the person who is suspected to have committed the crime) can charge a lawyer to investigate on that person's behalf, in order to prove innocence. The Pubblico Ministero can appoint experts to carry out examinations; and, when the examination cannot be repeated (for instance, an autopsy), he must inform the indagato, so that he can appoint another expert, to ensure his right of defense. In the case of interrogations, of searches and of seizures, the indagato can ask that his lawyer be present.
During the preliminary investigations, a Judge only seldom intervenes. The Giudice per le Indagini Preliminari (Judge for the Preliminary Investigations) controls the actions of the Pubblico Ministero, when the personal rights of the indagato are at stake. No indagato can be wiretapped, unless the Judge for the Preliminary Investigations has authorised it. All measures must be adopted by the Judge with an order, and he must also publish written explanations of his decisions.