Every citizen is granted specific rights under the constitution. To deprive a citizen of those rights, an officer must show probable cause. Probable cause is a reasonable belief that a crime has been committed. While an officer may detain an individual based on reasonable suspicion that a crime has been committed, an officer has no right to otherwise search you or conduct an investigation unless he or she has a reasonable belief. The distinction may sound specious, but legally, it is very important. If an officer did not have probable cause to conduct a search during a traffic stop, then the search was illegal and anything found during the search would be inadmissible in court.