The Fourth Amendment is all about search and seizure and personal privacy as it applies to criminal law. If a law enforcement officer violates the Fourth Amendment in order to obtain evidence that will be used against you in criminal court, for example, this evidence may be thrown out and cannot be used against you.
Let's take a quick look at the areas where the Fourth Amendment has jurisdiction
-- When a police officer apprehends you at the time of a traffic stop or arrest; and
-- When police search a location where someone can expect to have privacy -- such as a person's home, luggage, car, bag, clothing, body, hotel room, place of business or apartment.
In these circumstances, the Fourth Amendment provides individuals with specific rights. It prevents criminal prosecutors from using unlawfully obtained items as evidence against an accused person. In order for a search and seizure to be valid under the Fourth Amendment, police must:
-- Have a search warrant;
-- Have an arrest warrant; or
-- Have a reasonable belief, referred to as "probable cause," that the person being searched or seized has actually committed a crime.
Many New York criminal cases have been thrown out of court as a result of Fourth Amendment violations. For example, imagine a police officer performs a search on a vehicle, but the officer did not have a valid reason to do so. If the officer finds drugs in the car during this unlawful search, those drugs will not be admissible in court as evidence against the person who was allegedly in possession of them.
Source: FindLaw, "Search and Seizure and the Fourth Amendment," accessed July 26, 2017