172. Once its dimensions have been identified, the scene needs to be secured. A crime scene entry log should be opened and maintained until the crime scene has been fully processed. Securing the scene entails: (a) Limiting access: Access to the geographic area of the scene is documented and limited to relevant experts and investigators. Access that may have contributed to the contamination and degradation of evidence, as well as any evidence of a manipulation of the scene that may have occurred or could possibly occur, need to be identified and documented (b) Personnel safety: The scene is rendered safe for access for the identification, documentation and collection of evidence. In circumstances such as ongoing armed conflict, or areas where items such as unexploded ordnance, toxic agents, and/or booby-traps are suspected, specialists with expertise in rendering such items safe need to be consulted. They include explosive ordnance disposal personnel and chemical, biological and/or radiological experts. Precautions against coming under armed attack might also be necessary in some circumstances (c) Evidence security: Limiting access to a death scene entails establishing a chain of custody that originates when an individual crime-scene investigator identifies evidence. 173. The crime scene should be searched for evidence. Where possible, the search should be conducted jointly with an investigator who is aware of background information on the death, although great care should be exercised so as not to bias the investigation. The search criteria must, at a minimum, be documented in investigators’ notes. This serves to identify which items are pertinent to establishing a sequence of events and can link suspects, victims and other physical evidence with the scene of death. 174. Items of physical evidence need to be identified with unique photo markers (numerical and/or alphabetical). The site code also needs to be identified. This allows for their location and their relation to other items of evidence within the death scene to be comprehensively documented, including for inventory and chain-of-custody purposes. A standard marking system for all evidence should be introduced – see Paragraphs 94 to 97 on labelling. 175. Any forensic analysis, including but not limited to the crime scene, requires the following documentation methods: photography, measurements, note-taking and an inventory. These should all be cross-referenced against each other, to improve the independent understanding of a death scene and increase the credibility of the collected evidence. 2. Photographic documentation 176. The photographic documentation of a death scene and of any physical evidence is a twodimensional depiction of a three-dimensional space or object. Photographs should therefore be taken in sequence, with an overlap between one image and the next, allowing an outside observer or examiner to understand the spatial relationship between the items of evidence within a defined space such as a death scene. 177. The sequence in which such photographs were taken should be documented by a photolog, identifying, at a minimum, the identity of the photographer, the position of a photograph within a sequence, the time the photographs were taken and the location at which they were taken. Where the technology exists, digital cameras should be used. Check that the date and time on the camera is set correctly. Digital cameras can generate a sequential file-numbering system and include metadata embedded in the digital images themselves. Such metadata can include date and time, the camera’s technical settings and, when it is connected to a global positioning system (GPS) longitude and latitude information. Relevant information should be included in a photolog. The same data should be recorded if analogue (film) cameras are used. 178. Three types of photographs need to be included in the documentation of crime scenes and evidence: (a) Overview photographs visually establish the spatial dimensions of a crime scene. Overview photographs should be taken from the outside of the scene towards its centre, ideally from along the outside perimeter of the scene. If possible, photo markers should be distinguishable in these photographs 31