Under Fourth Amendment law, a seizure usually occurs in one of two instances: a seizure of a person, or a seizure of property.
A seizure of a person essentially occurs when law enforcement prevents someone from leaving. This does not have to be a physical act, rather it can also be what the person thought of the situation.
A seizure of property occurs when the government interferes with an individual’s possessory interest in that property.
“By contrast an individual is seized under the Fourth Amendment when a reasonable person, in view of all the circumstances of a particular case, would not believe he was free to leave.”
State v. Brannon, 388 S.C. 498, 503 (2010) (citation omitted)
“The test is necessarily imprecise, because it is designed to assess the coercive effect of police conduct, taken as a whole, rather than to focus on particular details of that conduct in isolation. Moreover, what constitutes a restraint on liberty prompting a person to conclude that he is not free to ‘leave’ will vary, not only with the particular police conduct at issue, but also with the setting in which the conduct occurs. While the test is flexible enough to be applied to the whole range of police conduct in an equally broad range of settings, it calls for consistent application from one police encounter to the next, regardless of the particular individual's response to the actions of the police. The test's objective standard—looking to the reasonable man's interpretation of the conduct in question—allows the police to determine in advance whether the conduct contemplated will implicate the Fourth Amendment. This ‘reasonable person’ standard also ensures that the scope of Fourth Amendment protection does not vary with the state of mind of the particular individual being approached.”
Michigan v. Chesternut, 486 U.S. 567, 573–74 (1988) (citations omitted)
“In the instant case, the police officer seized Petitioner within the meaning of the Fourth Amendment at the time the officer pulled up behind the vehicle Petitioner was driving, blocking the vehicle in and preventing it from driving away. At that point, a reasonable person in Petitioner's position would not have felt free to leave.
Because the seizure began at that point, the requisite reasonable suspicion likewise must have been present at the same time.”
Robinson v. State, 407 S.C. 169, 183 (2014) (citation omitted)
“We conclude that a person has been ‘seized’ within the meaning of the Fourth Amendment only if, in view of all of the circumstances surrounding the incident, a reasonable person would have believed that he was not free to leave. Examples of circumstances that might indicate a seizure, even where the person did not attempt to leave, would be the threatening presence of several officers, the display of a weapon by an officer, some physical touching of the person of the citizen, or the use of language or tone of voice indicating that compliance with the officer's request might be compelled. In the absence of some such evidence, otherwise inoffensive contact between a member of the public and the police cannot, as a matter of law, amount to a seizure of that person.”
United States v. Mendenhall, 446 U.S. 544, 554–55 (1980) (citations omitted)
“A ‘seizure’ of property occurs when there is some meaningful interference with an individual's possessory interests in that property.”
United States v. Jacobsen, 466 U.S. 109, 113 (1984)
“While the concept of a ‘seizure’ of property is not much discussed in our cases, this definition follows from our oft-repeated definition of the ‘seizure’ of a person within the meaning of the Fourth Amendment-meaningful interference, however brief, with an individual's freedom of movement.
United States v. Jacobsen, 466 U.S. 109, 114 (1984)
 State v. Brannon, 388 S.C. 498, 503 (2010) (citation omitted)
 United States v. Jacobsen, 466 U.S. 109, 113 (1984)