When it comes to crime scene processing, there is one rule that must be followed without fail: document everything. This means that before anything is touched, it must be photographed. This applies to the victim and any other items found at the scene, no matter how small or large. It is essential that the actual crime scene be captured in photographs to preserve the scene before any evidence is collected or the body is moved.
Under no circumstances should anyone draw a chalk line around the victim before they have been photographed, as this can disrupt the crime scene and make any evidence found near the victim inadmissible in court. The first step of processing a crime scene should be visual examination. The crime scene investigator should use their best judgment to identify potential evidence and areas where evidence may be located, as well as to confirm their initial assumptions about the type of crime scene they are dealing with. If the person responsible for documenting the crime scene has any artistic ability, detailed sketches of the crime scene can be made to help not only investigators but also lawyers and other courtroom personnel later on.
The exact location of the body should be noted, along with a thorough description of the crime scene. The crime scene technician should also create a rough sketch to illustrate the layout of the crime scene or to pinpoint the exact position of the deceased victim or evidence within the scene. Photographs should also be taken to record a visual representation of what the scene looked like and to capture elements of possible evidence. It is understandable that those with an interest in the property may want access as soon as possible, but the CSI should not be rushed or pressured into releasing the scene until their work is complete. Interviewing witnesses when they arrive at the crime scene is one of the first steps that must be taken in order to obtain accurate accounts of what happened.
If it is believed that an intruder entered through a window, then this area must be examined for shoe prints, tool marks, traces, and latent fingerprints. Interviewing witnesses immediately provides law enforcement personnel with their best chance of obtaining useful information from those present at or involved in the crime scene. Crime scene evidence is useless unless it is properly marked and packaged and a chain of custody is established from when it was collected. It is important to remember that protecting and preserving the crime scene is key when searching for any type of evidence. When undressing a victim, personnel must walk from one end of the crime scene to another and then return in the same direction they started.