With the establishment of Law 397 on December 7th, 2000, on the subject of Defensive Investigation, Defense faculty is granted, in the course of a Criminal Procedure, to avail itself of a private investigator (regularly authorized) for the research or verification of elements tested in support of defense and in favor of the client, with the aim of bringing out the objective truth of the trial.
In order to better orientate and carry out the commissioned investigations, it is essential that the private investigator knows a priori what tends to be the defensive strategy that the law firms intend to support, such as the Demolition Defense, finding elements of non-truth from witnesses or negative elements to demonstrate the lack of reliability, or the Alternative Defense, finding elements to dynamically envisage the facts, differently from that sustained by the prosecution.
The work of the private investigator consists mainly in the verification or search of sources of evidence (fingerprints, artifacts, eyewitnesses, objects, documents) and means of proof (testimonies, experiments, verification of facts, appraisals, consultancies).
The evidence is the final result of the investigation and may consist of videos or photographs (representative evidence), eyewitness testimony or hearsay (narrative evidence), or appraisals or verification of the aforementioned (reconstructive tests).
Further investigations may consist of direct tests (irrefutable factual evidence), indirect tests (circumstantial or marginal fact from the primary one, test thread), conclusive tests (documented evidence), negative tests (not existing) and positive tests (attainment from an alibi supported by testimonies or documents).