PART A - EVIDENCE OVERVIEW
Very often the collection of evidence begins at the crime scene. The next section of this subcourse will discuss
specific features of the crime scene.
PRESERVING THE SCENE
The success of a case depends heavily on initial actions and observations taken by the first investigator to
arrive at the crime scene. Although the actions taken to find and preserve physical evidence will vary from case
to case, certain procedures apply to all cases.
As you approach the scene your actions should be calm and deliberate. Always expect the worst. It is
better to take too many precautions at the crime scene than it is to take too few. Keep an open mind about the
crime. Reaching conclusions too soon may lead to carelessness and false moves, which may be disastrous. Errors
in safeguarding and inspecting the crime scene can never be corrected.
If there are injured persons at the crime scene, get them medical aid first. If enough MPs are on hand, the
steps needed to protect the crime scene should begin as you give aid to the injured or examine the dead.
You must prevent unneeded walking about. Take precautions to prevent walking in areas that are likely to
bear the impressions of footprints or tire tracks. Use caution and avoid places where possible clues may be found.
Avoid touching doors, doorknobs, light switches, floors, and windows. Avoid using the telephone or smoking at
the scene. Do not use the toilet, turn on the water, or use towels at the crime scene. The criminal may have used
the bathroom. He may have used towels to wipe bloodstains from himself or his weapons. Or there may be blood
caught in the sink or commode trap.
If you are an MP investigating a crime that will require the services of a USACIDC special agent, you must
protect the scene until help arrives. Do not move any items or disturb the bodies of deceased persons. Usually,
you cover a body only after it has been fully processed for evidence. If you cover it too soon, you could change
or destroy valuable trace evidence. Do not touch items or surfaces that are likely to yield latent fingerprints. Do
not allow any item to be removed from the scene without specific permission from the crime scene investigator or
the crime lab examiner who is in charge of the case. Restrictions must not be lifted until the person in charge has
specifically released the crime scene or, at least, until the search is done.
In extreme cases, you may need to move things that could be evidence from areas where they might be
destroyed or drastically affected by the elements or other unavoidable circumstances. However, moving evidence
before it has been fully examined and processed should be avoided if possible. If you move evidence
prematurely, its original position should be recorded in your notes. Take closeup photographs if you can.