Crime Scene Forensics - Arriving at the Scene of a Crime

Whenever a person dials 911 to report a crime, it ispose a threat. Whenever an offender is around, the
imperative that the first officer to arrive at theofficer arrests and handcuffs the person. Afterwards,
scene detain the person making the call and forbidthe officer helps out any victims who are around and
the individual from entering the crime scene. Anybodycalls for paramedics if needed. After completing these
who calls in to report a crime may have been atasks, the officer starts to preserve the crime scene.
witness to the incident or may have seen or heardIn addition, the officer may need to detain any
something out of place.suspects and witnesses and separate them to avoid
However, because the officer has no way ofcollusion. Collusion occurs when the detainees "get
knowing if the person who dialed 911 to report atheir stories straight" so that they all tell the same
crime is a witness or a suspect, allowing the individualthing to police. At this point, however, the officer
to access the scene of a crime can risk losing ormay not know which is which. A witness may turn
contaminating the evidence. After all, an offenderinto a suspect, and a suspect may actually be a good
may:witness. Moreover, the officer may have no legal
- Believe that reporting an incident removes him fromright to detain some witnesses and thus must jot
the focus of a subsequent investigationdown the name and information from each person
- Try to destroy, move around, or remove evidence.who leaves the scene.
Either of these circumstances can occur. Therefore, itIn the middle of any crime-scene preservation is a
is necessary that the first-arriving officer approachprinciple called Locard's Principle of Exchange. Locard's
the crime scene in an organized and logical manner.Principle of Exchange occurs when two individuals
This protects the evidence and other individuals whocome into contact with one another and exchange
may be there. Otherwise, the safety of the officer,any trace materials such as hair, fingerprints, or fibers.
his fellow officers, witnesses, victims, suspects, andAny person who enters the crime scene can leave a
even the offender may be at risk. Not to mention,piece of evidence of their presence, remove crucial
evidence may be destroyed.trace evidence on their clothes, shoes, hands, or alter
The first-arriving officer who responds to a call of aany evidence that stays behind. Therefore, access to
crime must make his own personal safety his utmostthe crime scene must be forbidden right away to all
concern and make sure that the offenders no longerwitnesses and suspects.