The Hungarian state security organs divided their investigation work into two phases: the confidential and the open investigation phases. In the confidential phase they collected data using operative methods in order to prove that an activity indicated crime or negligence, but evidence obtained this way could not be used in the criminal procedure. If the fact of crime was confirmed, the open investigation phase began, the objective of which was to provide legal force to the evidence obtained during the confidential investigation. The documents created during this procedure were collected in an Investigation File, which included documents related to the investigation in the cases of persons subject to criminal procedure.