One of the most important tools that a crime scene investigator has is the pictures taken at a crime scene. Crime scene photographs are used to record the crime scene in its original form, before evidence is collected and anything is moved around. Taking crime scene photographs, on either 35 millimeter film or with a digital camera, is one of the most important steps to processing a crime scene because it allows investigators to view the crime scene weeks, months or even years after the crime took place.
Crime scene photographs are important for preserving a record of the original crime scene. Photographs are normally taken at three levels: overall, mid-level and close-up. Overall shots show the overall crime scene. Mid-level shots show distances and relationships between objects. Close-up shots show the details of evidence or anything else relevant to the crime.
It is important that these photographs are taken before anyone has the chance to wander through the crime scene, potentially moving things from their original location. It is done after the nature of the crime has been determined and a general theory about the crime has been put together. This theory, which may include the criminal's entrance and exit points, any potential weapons and how the crime was committed, will help to direct the photographer towards the shots that need to be taken.
After they have been taken and developed, crime scene photographs become an essential part of the case file. Even though a sketch of the crime scene will also be created, the photographs provide investigators with the opportunity to return to the original crime scene to look for anything that may help to solve the case. Crime scene photographs can help investigators remember little nuances of the crime scene, and can be compared to witness and victim testimonies, allowing for accuracy checks.
Crime scene photographs are considered visual evidence, and can be used in court cases. The pictures must use scales, where appropriate. For example, the size of blood splatters could be shown by placing a quarter, or other small and easily identifiable object, on a clean surface near the splatters. The camera angles used must also be taken into consideration. Overall views of the crime scene must be taken from several different angles. Pictures of smaller objects and areas should also be shown from several different perspectives. In order for pictures to be usable, they must also be clear, without distracting dirt marks on the lens, deep shadows or blurring that would make details difficult to see.
