Other forms of indirect evidence that documentation teams may obtain include court transcripts, police and prison records, and photographs. Reports published by the media or other organizations are also potentially useful, although the credibility and independence of reports from secondary sources should be carefully evaluated. Whenever possible, the original document should be sought; court proceedings, for example, may require the original, rather than a copy. If a documentation team is planning to visit a particular site to collect evidence, they should try to retain assistance from relevant experts if any special expertise, e.g., forensic science, is required to evaluate the site. Documentation teams should also be careful not to disturb sites that might yield evidence or to draw unwanted attention to the site. They should seek to make careful, objective notes, including diagrams or maps. Audio and visual recording tools Audio recorders, video recorders, or cameras may be used to document nontestimonial evidence of human rights abuses. Although these tools may present some advantages, including the immediate impact of sounds and images and the relative speed and ease with which digitally stored information can be distributed, there are serious security and confidentiality risks associated with this form of documentation. Audio-visual recordings should therefore only be made if the “do no harm” principle can be respected. It is not recommended to use audio-video recordings to collect testimony. Recording tools should only be used to collect indirect evidence. Individuals, even those not providing testimony, should never be filmed, photographed, or recorded without their express informed consent. It is not necessary to take photos of witnesses, and doing so may create a risk of retaliation. In the rare event that testimony is recorded, every effort should be made to obscure the identity of a witness and it should be labeled in such a way that the identity of the individual is not disclosed. If a documentation team is confident that it can make such recordings without compromising the security of any respondents, it should take the following steps:     Try to use equipment that is discreet, e.g., a camera that is small and a dark color, rather than white, silver, or reflective. When using a camera, use it in silent mode; Practice using cameras without needing to look through the lens (i.e., take shots down by the photographer’s hip or, if using a phone camera, as if the user is normally handling a phone); When using a camera, always take more than one photo of each subject; Try to download data to an encrypted online database (such as Martus www.martus.org); if downloading onto a personal computer, use encryption software and a secure password to lock the file. 19