stop and frisk
A stop-and-frisk refers to a brief non-intrusive police stop of an individual. The Fourth Amendment requires that before stopping the suspect, the police must have a reasonable suspicion that a crime has been, is being, or is about to be committed by the suspect. If the police reasonably believe that the suspected individual is armed and dangerous, the police may frisk them, meaning that the police will give a quick pat-down of the suspect's outer clothing. The frisk is also called a Terry Stop, derived from the Supreme Court case Terry v. Ohio, 392 U.S. 1 (1968). The Court in Terry held that a stop-and-frisk must comply with the Fourth Amendment, meaning that the stop-and-frisk cannot be unreasonable. According to the Terry Court, a reasonable stop-and-frisk is one "in which a reasonably prudent officer is warranted in the circumstances of a given case in believing that his safety or that of others is endangered, he may make a reasonable search for weapons of the person believed by him to be armed and dangerous." Stop-and-frisks fall under criminal law, as opposed to civil law.
Scope of A Reasonable Stop
In Rodriguez v. United States, 575 U.S. (2015), the Supreme Court held, "[A] police stop exceeding the time needed to handle the matter for which the stop was made violates the Constitution’s shield against unreasonable seizures. A seizure justified only by a police-observed traffic violation, therefore, 'become[s] unlawful if it is prolonged beyond the time reasonably required to complete th[e] mission' of issuing a ticket for the violation." Specifically in Rodriguez, a police officer completed his Terry Stop, and he then had his police dog perform a dog sniff search on the suspect. The Court held that that sniff search violated the Fourth Amendment as it was prolonged beyond the time reasonably required to complete the stop.
Criminal evidence found during an unreasonable search (i.e. evidence that the dog sniff would have detected in Rodriguez after the police officer had already completed his search) is subject to the exclusionary rule and will be excluded from being introduced at trial.
In Utah v. Strieff, 579 U.S. (2016), the Supreme Court held that when a police officer finds there is a "valid, pre-existing, and untainted arrest warrant" for an individual, then any evidence obtained from a stop of that individual will be admissible in court, even if the stop would otherwise violate the Fourth Amendment. The Strieff Court referenced its earlier ruling in Brown v. Illinois, 422 U.S. 590 (1975). In Brown, the Court held that evidence "obtained by the exploitation of an illegal arrest" is not admissible. The Brown Court used a three-factor balancing test regarding the admissibility of the evidence:
