Copy and paste is your friend, people:
(from site linked in reply #2):
**What exactly is Reasonable Suspicion? **
Reasonable suspicion is defined by a set of factual circumstances that would lead a reasonable police officer to believe criminal activity is occurring. This is different from the probable cause (what a reasonable person would believe) required for an arrest, search, and seizure. If the stop and frisk gives rise to probable cause to believe the detainee has committed a crime, then the police officer should have the power to make a formal arrest and conduct a search of the person.
**What is a Stop? **
What constitutes a stop and frisk? Can one be stopped and not frisked? Or does one action always follow another? A stop is a seizure of a person. There are two types of stops: (1.) a show of force and (2.) a show of authority. With a show of force, an officer must physically lay hands on the person with the intent of detaining them. In a show of authority, the officer’s look, demeanor, and display of authority persuades a person to submit to authority. The key element in this type of stop is that the individual must submit to the show of authority, believe they have been seized, and feel compelled to cooperate.
A Justified Stop
A stop is justified if the suspect is exhibiting any combination of the following behaviors:[ol]
[li]Appears not to fit the time or place.[/li][li]Matches the description on a “Wanted” flyer.[/li][li]Acts strangely, or is emotional, angry, fearful, or intoxicated.[/li][li]Loitering, or looking for something.[/li][li]Running away or engaging in furtive movements.[/li][li]Present in a crime scene area.[/li][li]Present in a high-crime area (not sufficient by itself or with loitering).[/li][/ol]**What is a Justified Frisk? **
A frisk is a type of search that requires a lawful stop. It involves contact or patting of the person’s outer clothing to detect if a concealed weapon is being carried. The frisk doesn’t necessarily always follow a stop. The law of frisk is based on the “experienced police officer” standard whereby an officer’s experience makes him more equipped to read into criminal behavior than the average layperson.
The purpose of a frisk is to dispel suspicions of danger to the officer and other persons. The frisk should only be used to detect concealed weapons or contraband. If other evidence, such as a suspected drug container, can be felt under the suspect’s clothing, it can be seized by the officer. This is called the “plain feel” doctrine. To pass the plain feel test, the item must have an immediately apparent character or quality of being contraband or evidence.
A frisk is justified under the following circumstances:[ol]
[li]Concern for the safety of the officer or of others.[/li][li]Suspicion the suspect is armed and dangerous.[/li][li]Suspicion the suspect is about to commit a crime where a weapon is commonly used.[/li][li]Officer is alone and backup has not arrived.[/li][li]Number of suspects and their physical size.[/li][li]Behavior, emotional state, and/or look of suspects.[/li][li]Suspect gave evasive answers during the initial stop.[/li][li]Time of day and/or geographical surroundings (not sufficient by themselves to justify frisk).[/li][/ol]
