A/HRC/12/19 page 7 may be in international tribunals or domestic courts or “hybrid” courts that have both national and international elements. Prosecutions focus on individual perpetrators, while trial monitoring focuses on the institutional structures in the legal system. Both use records extensively. 20. Investigations and prosecutions use whatever documentary materials are pertinent to the matter being investigated: records of Government (especially records of the military and the police and security services, overt or covert); records of non-governmental and international organizations; records of churches and businesses, banks, schools, hospitals and morgues; copies of radio and television broadcasts; records of Government-owned media. They use all physical types of records: paper, electronic, photographic, mapping and satellite imagery and databases. 21. When determining whether an international crime has been committed requires establishing the existence of a policy or pattern of systematic violations, understanding the flow of information to or from the leaders, whether they are army generals, presidents, or leaders of rebel groups, is crucial. This requires a serious analysis of the records of the highest levels of the institution; the registers of documents sent and received can be especially useful, as are reports from subordinate units to headquarters. 22. Prosecutors may obtain records from NGOs, international organizations and church groups who were present in the region when the crimes occurred. Pertinent records created by these institutions may include, for example, regular reports back to the entity’s headquarters, interviews with persons they are assisting, and correspondence with the local authorities as the organizations struggle to get permission to bring in or ship out goods, aid workers, or refugees. Because many aid organizations have substantial experience in working in countries in crisis, their records providing an on-the-scene neutral point of view on events may have special probative value. Truth-seeking and the right to know 23. Research on the fate of missing persons can include searching through records, interviewing people, exhuming burial sites and conducting DNA tests. NGOs often support or lead the demand to know the fate of the disappeared, and some transitional Governments establish a special body to resolve cases of disappearance. Just as individuals search for information on themselves or others, the wider public seeks an answer to what happened within the society as a whole. During the last quarter of the twentieth century, one of the most popular vehicles for seeking societal truths has been the truth commission. The updated Set of Principles declares that “[a]ll persons shall be entitled to know whether their name appears in State archives” (ibid., principle 17 (b)). 24. Truth commissions are not bound by the formal rules of evidence required by a prosecution, and so they use a broader range of records than any other transitional justice institution. Records of Government (especially military, police, security services, civil registries, land records, courts and prosecutor records), records of NGOs, radio and television broadcasts, records of international organizations and personal papers have all been used by a truth commission. Most truth commissions take extensive oral testimonies whose records can help substantiate, expand upon or disprove allegations of human rights violations.