However, the probable cause of the search or seizure cannot be regarded as a lie in case the only evidence of criminal activity is the affirmation of suspicion made by law enforcement officer. In this case, special attention was paid to the availability of the probable cause to stop individuals in the street. Constitution protects citizens from unreasonable search and seizure, but interpretations of "reasonableness" have changed throughout history.The line between lawful and unlawful vehicle searches can seem a bit blurry, and is frequently redefined by courts, so understanding the law is in every motorist's best interests.According to researchers, “warrantless arrests are more common than those with a warrant”(Emanuel, 2009, p. However, warrantless searches depend on the availability of one of the exceptions to the warrant requirement to be lawful. In other words, a law enforcement officer who is planning to arrest an individual without a warrant must be based on the availability of the probable cause to believe that an individual has been involved in criminal activity. In fact, the term “search warrant” can be defined as a legal written order signed by the court officials to authorize a law-enforcement officer or government agent to conduct a search or seizure (Buckles, 2006).The probable cause forms the basis of legality for arrests, searches and seizures without a warrant. In other words, a search warrant authorizes to conduct a search for a person (or persons) suspected of a crime. Supreme Court ruled that the warrantless arrest was legal.Constitution states as follows: "The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized." ... They came to her house, and she refused them in without a search warrant. The Fourth Amendment Warrant Requirement that governs the search of a crime scene is that “authorities must comply with the Fourth Amendment to the U. The court should rule that the search is reasonable under the particular circumstances (Buckles, 2006; Kleiman, 2011). Supreme Court has ruled that there should be a probable cause for the search or seizure when the circumstances of the case form the basis for an individual to believe that he/she has committed a crime (Kleiman, 2011). Today it is necessary to classify many exceptions to the search and seizure warrant requirements (Lippman, 2010). Justifications for warrantless arrests and searches depend on the availability of the probable cause. Gordon (1978), “a warrant is never required to make either an arrest or a search when exigent circumstances exist”(p.1550). Supreme Court ruled to give postal inspectors the right to perform warrantless searches and arrests based on probable cause, even if they have to arrest someone in public. The law enforcement officers had enough evidence used to produce the probable cause to believe that the crime was committed by Santana.Moreover, the application for a lawful search warrant to a particular case should be supported by a sworn statement made by a law enforcement officer in the court. The term “probable cause” means some probable reason for having a belief in the fact that an individual has committed a crime. There are three important cases that illustrate various aspects of the ability of law enforcement officers and government agents to conduct arrests without a warrant. In the case (1980), the Court found that the police entry was unconstitutional and “beyond the scope of the police’s right to make warrantless arrests” (Emanuel, 2009, p. The police entered the house when there was no one inside it. Supreme Court has ruled that police officers have the right to stop suspicious individuals in the street in order to search them for weapons (Buckles, 2006; Emanuel, 2009).Nevertheless, there is justification for warrantless searches at the time of an individual’s arrest.There are three fundamental reasons for warrantless searches during the arrest: the chance to identify if the person is concealing weapons, the need to prevent the escape of the person during the arrest procedure and the need to prevent the destruction of important evidence (Lippman, 2010). Constitution is a good example of legislation that can be used to prevent unreasonable search or seizure. The major goal of the police officers who are allowed to conduct warrantless searches and seizures is to preserve evidence.