Seizures and the 4th Amendment

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.


Seizures of People

Crime in Front of Officer

If a felony or misdemeanor is committed in front of an officer and the officer sees it, then a warrantless arrest is okay.

Reasonable Grounds Felony Occurred

If there is probable cause a felony (doesn't include misdemeanors) occurred, then a warrantless arrest is okay (Watson).

Moment of Seizure

A seizure doesn't occur unless the totality of the circumstances would lead a reasonable person to believe he wasn't free to leave. There must be a show of authority, suspect believes they cannot leave, and the suspect submits to the officer (Mendenhall, Hodari D.).

Arrest for Minor Offense

Unless prohibited by state law, officers may arrest anyone for even the most minor offense if the officer has probable cause a crime was committed in front of him/her (Atwater).

Vehicle Passengers

Passengers are seized when the car is pulled over (Brendlin).

Pulling People Over

Officers may pull over people for even minor crimes (Atwater).

Failure to Submit to Show of Authority

If a suspect fails to submit to a show of authority, then they are not yet seized and officers may pursue the suspect (Hodari D., Scott v. Harris).


Use of Force

Deadly Force

Apprehending someone by shooting them is a seizure, and deadly force may not be used unless it is necessary to prevent the escape, and the officer has probable cause to believe that the suspect poses a significant threat of death or serious physical injury to the officer or others (Garner, Scott v. Harris).

Excessive Force

Excessive force should be examined under objective reasonableness under the circumstances, and not subjective concepts like malice (Graham).


Terry Stop, Terry Frisk, and Arrests

Terry Stop

To conduct a Terry stop, officers only need reasonable suspicion the suspect either committed a crime or was about to commit a crime based on circumstances as a whole, not in isolating (Terry, Arvizu, Sokolow). To be a stop and not an arrest during an investigative detention, it must be minimal in duration (US v. Sharpe).

Terry Frisk

To legally frisk someone, the officer only needs reasonable suspicion that the suspect is armed or dangerous to an extent that they may be a danger to the officer or the public (Terry). Officers may also conduct investigatory searches with dogs with RS (Sokolow).


To arrest someone, officers need probable cause.

Taking Someone for Questioning

Taking a suspect to a police station for questioning is an arrest (Dunaway).

Taking a Suspect to the Station for Fingerprinting

Taking a suspect to a police station for fingerprinting is an arrest that requires probable cause (Hayes v. Florida).

Totality of Circumstances Stop

Police must base stops on the totality of the circumstances, rather than determine the individual facts in isolation. Officers may infer from their observations and experience what the suspect is doing, attempting to do, or preparing to do (Arvizu, Sokolow).

Informant Tip to Terry Stop and Frisk

When officers rely on reasonable suspicion to make Terry stops based on informant tips, the quality of the informant tip does not have to be as reliable as a tip to establish probable cause. However, there is still a baseline for corroboration and reliability that must be met in order to trigger RS (Alabama v. White, Florida v. J.L.).

Suspect Flight for Terry Stop

The totality of circumstances, including evasive behavior in dangerous or high-crime neighborhoods, triggers RS based on commonsense inferences about human behavior (Illinois v. Wardlow).

Taking a Suspect from a Public Area of an Airport to a Room

Taking a suspect from a public area in an airport to a room constitutes an arrest (Royer). An exception is if the person comes voluntarily without being ordered to do so by the officer (Mendenhall).

Fingerprinting in the Field

It is unclear if fingerprinting in the field is a violation of the 4th amendment because it has not been directly addressed by the Court (Hayes v. Florida, Davis v. Mississippi).

Detaining Someone for Extended Period of Time

Police may detain people for at least 30-40 minutes without the seizure becoming an arrest (US v. Sharpe).