Videos and photographs captured by witnesses who provide them to investigators could provide crucial corroboration of witness testimonies. If time and circumstances permit, it will be important for the investigator to view the photographs or videos in the presence of the witnesses and to ask them to explain the contents. (d) Official documents A range of official documents, including autopsy reports, court records, military personnel records, official press statements and public speeches, may be collected by investigators. As a general rule, original documents should not be collected, but rather copied or photographed and such copies/photographs stored with a detailed information report (see sect. 1 (c) above). All official documents relevant to the issues or incidents under investigation have some value to the inquiry. Some may be offered to the commission/mission, while in other instances investigators may stumble across them, for example, in an abandoned detention centre or military barracks. Investigators should guard against spurious or planted documents, designed to mislead the investigation. A local person familiar with the formatting and certification of official documents could assist in assessing the authenticity of the documents, by noting such clues as a missing stamp or misplaced signature. (e) Satellite images Commercially available overhead satellite images can be very valuable to investigations by providing information on what existed on the ground during a specific incident. While satellite images may not be able to show how the actual incident unfolded, they provide important contextual information. A comparative analysis of the “before” and “after” images could provide information on, for example, the extent of the damage, the presence of the perpetrators and types of vehicles in the area. This information from an independent and impartial source could corroborate victim and witness testimonies and also allow the commission/ mission to challenge the perpetrators’ version. Satellite images could also corroborate the date on which an incident may have occurred. While they may not provide the exact date, they help to provide a date range that could support a victim or witness testimony. If investigators do not have access to sites, satellite images provide an alternative source of information. Investigators will have to obtain some information about the incident (date and place) from media reports, victims or witnesses so that the correct and best images can be obtained to support their investigations. GUIDANCE AND PRACTICE 45