Ask crime scene technicians to name the biggest problem that they encounter
on the job and you will consistently hear the same response--crime scene
contamination by curious officers, detectives, and supervisors. Whether called
evidence technicians, identification bureau officers, or laboratory specialists,
either civilian or sworn, most personnel responsible for the processing of crime
scene evidence find the same problems repeated by the same
"offenders."1 The unintentional contamination of
crime scenes appears to be a problem that will not go away without written
departmental policies reinforced by a strong foundation in training.
JUST LIKE TELEVISION
Very early in their careers, most law enforcement officers realize that the
police work they see depicted on television and in the movies bears little
resemblance to their jobs. It is something of an anomaly, therefore, that many
of these same officers seem to believe that crime scene work should be performed
as it is on the screen--murder scenes filled with loitering blue uniforms and
multitudes of detectives hovering over bodies, with crime scene personnel
appearing just long enough to snap an occasional picture or to dust a piece of
furniture for fingerprints. Officers who work under this misconception do not
seem to understand that a crime scene is no place for a crowd.
LOST EVIDENCE, LOST OPPORTUNITIES
Widespread trampling of crime scenes can prove very damaging to investigations. Often, it results in several of the more sensitive forensic techniques--such as trace analysis, bloodspatter interpretation, and DNA comparison--not being used to their fullest potential. Crime scene technicians know the futility of collecting hair or fiber samples after a roomful of officers have shed all over the scene. Footwear and tire track evidence is rarely recognized as valuable in departments where officers routinely wander unimpeded through crime scenes.2 On occasion, this can seriously hamper investigations.
Not long ago, a sheriff's department was forced to conduct a mass fingerprinting of its detective unit after a particularly sensational homicide crime scene became overrun with curious personnel. Considerable time and effort went into eliminating officers' fingerprints from the pool of legitimate prints. In another case involving a different agency, a set of crime scene photographs showed supervisory personnel standing on a blood-soaked carpet.
When the integrity of fingerprints and shoeprints is jeopardized, it is time
for agencies to rethink their approach to crime scene work. While departments
have tried artificial means of scene protection--such as having visitors sign
release forms agreeing to provide elimination fingerprints, hair samples, and
semen specimens, or establishing two-perimeter crime scenes (the inner perimeter
reserved for real forensic work)--these responses are mere salves for a problem
that demands more meaningful attention.3
SETTING AN EXAMPLE
The role of detectives and supervisors in protecting crime scenes cannot be overstressed. These individuals ultimately are responsible for an investigation. Investigators who conscientiously limit the number of visitors to a crime scene ultimately may save themselves a great deal of legwork.
The simplest and most productive way for supervisors and detectives to discourage crime scene contamination is to set a good example by their own behavior. If a lieutenant walks around a crime scene at will, opening drawers and rifling through closets, what could be the harm in other officers doing the same? If a detective sergeant fails to implement a sign-in log for scene visitors, what is there to limit "drop in" visits by curious patrol officers? It is in the best interests of case investigators to set a good example and to make sure others follow it.
To further enhance the protection of evidence, police administrators should draft and enforce a written policy regarding crime scene protection and preservation. The policy not only must be clear but also must carry the same weight as any other departmental rule. Police administrators should not tolerate curiosity as an excuse for unchecked visits to the scene of a crime. Administrators, perhaps in conjunction with the local prosecutor's office, should write and enforce the rules, and like supervisors and investigators, set an example by their own behavior.4
Prosecutors who have lost cases due to crime scene contamination could be an
invaluable source of ideas in the formation of policy. Likewise, administrators
should take advantage of the technical knowledge of laboratory and crime scene
specialists when formulating the department's policy.
The primary responsibilities of initial responders to a crime are to preserve life and to control suspects and witnesses. Then, shifting their focus somewhat, responding officers must take steps to preserve the integrity of the scene's physical boundaries. While this may not be a problem for those officers who were once taught the importance of protecting crime scenes, others--including supervisors, media relations personnel, and administrators--sometimes have trouble leaving well enough alone at a crime scene. 5
A department's written policy should provide a uniform procedure to restrict unnecessary access to crime scenes. A crime scene policy should contain the following elements:
This final element means that any supervisory officer who visits the scene to "have a look around" must stay at the site until either the crime scene technicians finish their work or a higher ranking officer arrives. Needless to say, this simple requirement goes a long way to discourage pointless tourism.
An officer attempting to secure a crime scene who finds the post regularly
overrun by curious commanders must have the means to protect the scene, enforce
department rules, and deal with superior officers. This is often a difficult
balancing act. A clearly-written, well-enforced policy helps to level the
ADDRESSING FUTURE PROBLEMS
In addition to a clearly defined written policy, departments should also
address the problem of crime scene contamination by instructing new officers to
follow approved practices. This is best accomplished during basic academy
instruction by having crime scene specialists discuss the department's policy
and the importance of protecting forensic evidence. As more officers become
trained in proper practices, the risk of future crime scene contamination
Crime scenes often yield forensic evidence that leads to the apprehension of
dangerous criminals. Perhaps just as often, though, potentially valuable
evidence is destroyed or rendered useless by careless behavior at the crime
scene. Clearly written directives and training for new officers in this area
will help agencies to resolve the problem. However, the ultimate responsibility
rests with administrators, supervisors, and detectives to reinforce positive
conduct by setting a good example for other officers to follow.