For a traditional law enforcement search to be considered reasonable, you need to establish one of two requirements: (1) warrant based onprobable cause; or (2) an exception to the warrant requirement. Probable cause exists where the situation warrants a man of reasonable caution to believe, based on the totality of the circumstances as he understands them, that an illegal offense is being committed by the person about to be arrested. The probable cause standard warrants more than just a reasonable suspicion, but necessitates less than a preponderance of the evidence requirement. Another important fact regarding probable cause determinations is the fact that it must exist at the time of the search or seizure of a suspect. The case of Illinois v. Gates sets out the requisite probable cause determination in the issuance of a warrant: in light of the totality of the circumstances, there is a “fair probability” that contraband or evidence of a crime will be found in particular place in which a law enforcement officer is requesting admission.Search warrants are always preferred, but searches and seizures most often occur without a warrant. In order for a search warrant to be reasonable and valid, two elements need to exist: (1) issuance by a neutral and detached magistrate; and (2) adherence to the particularity requirements. During the process of a warrant application, a police officer prepares the application for a warrant with a sworn affidavit attesting to the probable cause enclosed, and then it goes to a judge to sign off on. The requirement for a neutral and detached judge establishes credibility that the warrant is actually based on probable cause, as evidenced by the belief of two independent parties. In order to satisfy the particularity requirement, the warrant must adequately describe the place to be searched and the person or things to be seized.
Arrests are the most intrusive types of “seizure,” and therefore the Fourth Amendment applies when a government official arrests a person. Generally, law enforcement officials are supposed to apply for and obtain an arrest warrant before actually arresting an individual. Similar to the search warrant requirement, an arrest warrant must be reasonable as evidenced by a probable cause belief that the specific person committed the crime. However, if a police officer makes an arrest in a public place, then no arrest warrant is required. Another exception to the arrest warrant requirement is the rule that a police officer does not need to get an arrest warrant if he is in “hot pursuit of a fleeing felon.” If the police arrest someone in a third person’s home, they would need a search warrant. However, if they arrest you in your own home, then the arrest warrant is sufficient to meet the Fourth Amendment requirements. Lastly, with regards to the use of deadly force during an arrest, the court in Tennessee v. Garner held that a police officer must have probable cause to believe the suspect poses a “threat of serious bodily harm” to either fellow officers or other people, in order for deadly force to be considered reasonable.
