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. - Fourth Amendment to the Constitution of the United StatesReasonable SuspicionReasonable suspicion, like the related concept of probable cause, comes from the 4th Amendment's protection against unreasonable searches and seizures. Where probable cause, though, concerns having sufficient evidence to issue a warrant or make an arrest, reasonable suspicion pertains to police having sufficient evidence to detain, question, or frisk someone suspected of committing a crime.What this means is that to detain and question someone, police must have more than a simple hunch that the suspect has been involved in criminal activity. Instead, the standard is this: Would a reasonable person conclude that the available evidence suggests that a crime has been, or soon will be, committed? Law enforcement would most likely have "reasonable suspicion" to detain and question someone who:
- is running away from a crime scene;
- is driving a vehicle that is the same make and model as one involved in a crime;
- has physical characteristics matching those of someone sought for a crime;
- displays a gun or other weapon in a public area;
- or is seen on surveillance video leaving a building immediately after a theft is reported.