The collection of evidence, and especially material evidence, in relation to the crimes of organized crime, terrorism, corruption and crimes against international humanitarian law puts the police and judicial authorities before great challenges. Organized crime and terrorism have, over time and evolution, become enormous security risks and threats and, at the same time, the main issues of contemporary society. As criminal groups and organizations have more and more sophisticated and more secretive approaches to the commission of crimes, the police, the judiciary and the prosecution have increasingly serious problems in their discovery, clarification and proving. Given that organized crime attempts to 'eliminate witnesses' of its activities, it is necessary for the state to react energetically in order to find them. As such persons are a serious threat to members of criminal groups and organizations, their security is continuously threatened. It is therefore necessary to provide them with serious protection by conventional security agencies, which is undoubtedly the most comprehensively achieved within the framework of the program of protection of participants in criminal proceedings.