The agent of private investigators, more commonly called private detectives, collects for the requesting parties, physical or moral persons, clues of various kinds, of private or public types.
Thes clues enable the detective to establish, within the law, the respect of the accepted standards of good behaviors ans personal freedoms.

Material elements of evidence or presumption of evidence help to determine, as far as possible, the revelation of trhth or to permit the production of the evidence or presumption of the evidence thanks to the production or the identification of concreated or unknow elements and if necessary, before the competent court of law.