The Fourth Amendment to the United States Constitution provides that people have the right to be free from unreasonable searches and seizures. Over the years, courts have interpreted the Fourth Amendment to mean police officers must obtain a warrant before conducting a search. While warrantless arrests are presumptively invalid, there are several fairly large exceptions to the warrant requirement.
Perhaps the most common exception to the warrant requirement is that an officer can make a warrantless arrest, “if there is probable cause to believe that a criminal offense has been or is being committed.” This exception is the basis for most site arrests, where a police officer witnesses a crime, or has the victim of the crime identify the alleged offender, and arrests the suspect at the scene. A recent state appellate decision in a California robbery case illustrates how courts view warrantless arrests and how police officers try to get around the warrant requirement.
According to the court’s opinion, police were investigating a series of robberies that took place in 2012. During the investigation, the assigned officer reviewed surveillance video of several of the robberies. Four days after the most recent robbery, the officer was responding to a report of another robbery. The report indicated that the suspects were two black males, one taller than the other. The detective thought that these might be the men responsible for the robberies he was investigating.