A seizure under the Fourth Amendment will only occur "when the officer, by means of physical force or show of authority, has in some way restrained the liberty of a citizen".
In Popple v. State, 626 So. 2d 185 (Fla. 1993), the Supreme Court of Florida identified three levels of police-citizen encounters.
The first level, a "consensual encounter," involves minimal police contact and does not invoke constitutional safeguards.
During a consensual encounter, an individual is free to leave at any time and may choose to ignore the officer's requests and go about his business. Popple, 626 So. 2d at 186.
The second level is an "investigatory stop," during which an officer "may reasonably detain a citizen temporarily if the officer has reasonable suspicion that a person has committed, is committing, or is about to commit a crime." Id. (citing § 901.151, Fla. Stat. (1991)).