Getting Back to the Basics Edmond Locard ’ s “ Principal of Exchange ” holds that during the commission of a criminal act , certain physical items and other evidence may be deposited in the scene . “ Wherever he steps , whatever he touches , whatever he leaves , even unconsciously , will serve as a silent witness against him … Physical evidence cannot be wrong , it cannot perjure itself . It cannot be wholly absent . Only human failure to find it , study and understand it can diminish its value ” ( Kirk , 1953 ). It is easy for an officer to become complacent with some types of crime scenes ( e . g . entering autos , burglaries ) and simply go through the motions of collecting and reporting information . As the type of evidence to be collected becomes less common , such as DNA , officers tend to pay less attention to locating and collecting it .
To avoid this , officers must first display the diligence and initiative to search and look for evidence . Once the evidence is identified , they must have the skills to properly collect and store the evidence . Just like an officer ’ s marksmanship skills , the ability to potentially locate evidence , dust for fingerprints , photograph a scene , and other investigative actions are perishable skills . Because of this , it is important for the officer processing a scene to acknowledge the need to continuously hone their skills to not only identify and understand each evidentiary item but capture the scene with jury presentation in mind .
Scene Documentation Proper documentation enables a jury to be transported from the courtroom back to the crime scene , provides recall for investigators after the fact , and provides critical information to conduct a post scene analysis of evidence . “ Crime scene reconstruction begins with a systematic , meticulous , and competent endeavor by the crime scene processing team ” . While advanced concepts of crime scene reconstruction , such as bloodstain pattern analysis or flight path determination in shooting incidents , may not be warranted in property crime cases , the analytical approach that reconstruction takes is still pertinent .
Documentation can be divided between three categories : written notes , photographs , and diagraming .
Written Notes : Written notes of the observations in an incident report convey information that cannot be easily depicted . To accomplish this , reports must go beyond simply establishing the elements of the crime . Victim statements , the ambient temperature , and odors within a scene are all examples of the details an investigation can hinge upon . The scene should be
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