Physical evidence covers any and all objects that can establish that a crime has been committed or can provide a connection between a crime and its victim or a crime and its suspect. If physical evidence is to be effectively used for assisting the investigator, its presence first must be recognized at the crime scene. If all the natural and commercial objects within a reasonable distance of a crime were gathered so that the scientist could discover significant clues from them, the overflow of material would quickly immobilize the laboratory facility. Physical evidence can only achieve its optimum value in criminal investigations when its collection is performed with selectivity done by the collector’s thorough knowledge of the crime laboratory’s techniques, capabilities, and limitations. Even though it is true that present-day technology has given the crime laboratory capabilities far exceeding those of past decades, these advances are no excuse for contentment on the part of criminal investigators. Crime laboratories do not solve crimes; only a thorough and competent investigation conducted by professional police.