Each of these bags is accompanied by a “custody chain” document; this document is to be filled out by any officer who wishes to use or view the evidence. This is necessary to reduce the loss of evidence and cross contamination by individuals who should not have contact with it.
The area is photographed in meticulous detail and any signs of injury such as bloodstains are marked, numbered and photographed. These photographs are often important in the piecing together of an event so that officers who were not able to attend the scene can get an understanding for how it looked. Nowadays with the advent of technology digital technology such as video cameras are also used to record the nature of the scene.
Fingerprints are taken where possible and if the crime scene is outdoors the area is marked out and searched. Internal crime scenes are photographed, blood spatter patterns are measured and documented, and bloodstains on carpets and floors are measured for radius.
Regardless of the location of a crime scene it is imperative that all of those personnel involved in the recording and preserving of it are dressed correctly in protective clothing which are used to reduce the risk of bringing materials from other locations to the scene of the crime.
2.2.1 Locard's exchange principle. In forensic science, Locard's principle holds that the perpetrator of a crime will bring something into the crime scene and leave with something from it, and that both can be used as forensic evidence
2.2.2 When a person is arrested, is not just standing in front of the judge and being convicted, there should be