The OHCHR Fact-finding Mission relies on resources of the United Nations Mission in the Central African Republic to visit a remote location. UN / OHCHR Photo a good reason for the inconsistencies, for example, new buildings may have been constructed or trees chopped down since the time the person was last at the site. Investigators should conduct a detailed examination of a site and document its key features as accurately as possible by taking photographs and recording videos, drawing maps or sketches, and by taking detailed notes of their observations. As a general rule, investigators do not collect physical objects that may constitute evidence in criminal proceedings, but rather record them in detail through photographs, videos and drawings. In very exceptional circumstances investigators may have to exercise judgement as to whether they should go further than merely document and actually collect physical information, for instance if there is a risk that the object may otherwise be destroyed or irretrievably lost. In such cases, ensuring strong documentation of the handling, transport and storage of the items collected, also known as “chain of custody” or continuity, is essential. (d) Public hearings Commissions/missions have occasionally used public hearings to gather information on incidents or issues covered by the mandate (Gaza (2009) and Democratic People’s Republic of Korea (2013)). Public hearings have significantly raised the visibility of the inquiries conducted by the commissions/missions. Participants in the public hearings have included (a) victims and witnesses of alleged violations of human rights and 54 COMMISSIONS OF INQUIRY AND FACT-FINDING MISSIONS ON INTERNATIONAL HUMAN RIGHTS AND HUMANITARIAN LAW