Types

• There are four types of probable cause: observation, expertise, information and circumstantial evidence. Observation is information gathered by officers by using their senses. Expertise refers to an officer's special training and skills to detect criminal activity. Information is statements given by witnesses or victims. Circumstantial evidence implies that crime has been committed but does not prove it.
  
  

Felony Cases

• In Missouri, a felony case begins with a preliminary hearing. Those testifying are placed under oath and testimony is given to determine if the case will go to trial. The prosecutor provides evidence that there is probable cause that the defendant committed the crime, whereas the defense attorney tries to disprove the probable cause. If the judge believes enough probable cause has been presented, the case goes to trial; if not, the case is dismissed.
  
  

Search Warrants

• Probable cause must be given for a judge to approve a search warrant. Any evidence that is collected without probable cause is not admissible in court.