The Fourth Amendment does not apply to abandoned property. Abandoned property may be seized without a
search authorization. Any person may seize abandoned property.
Reasonable Expectation of Privacy
The Fourth Amendment takes into account the "Reasonable Expectation of Privacy" test. Suppose an individual
was in an area that he or she expected to be private. What would happen if the government intruded into that
area? This was tested in a Supreme Court case, Katz v. United States, 389 U.S. 347 (1967). Federal Bureau of
Investigation (FBI) agents placed an electronic listening device on the outside of a telephone booth.
Conversations by Katz were recorded. This evidence was judged inadmissible. The FBI (the government) was in
violation of a reasonable expectation of privacy. The court said that the Fourth Amendment may even apply
where no physical intrusion such as "protected area" or "trespass areas" are involved. Consequently, any analysis
of a search and seizure must begin with the "Reasonable Expectation of Privacy" test. See Figure 1-1.
Figure 1-1. Fourth Amendment Violation by the Government.
Evidence that is obtained in a way that violates the Fourth Amendment may not be admitted into court. This is
called the "Exclusionary Rule." The Exclusionary Rule is the primary way the Fourth Amendment is enforced.
The rule was created to deter officials from violating the Fourth Amendment. To use the fruits of a search as
evidence in court, the Fourth Amendment must not be violated while seizing the evidence.
Fruit of the Poisonous Tree
"Fruit of the Poisonous Tree" refers to evidence that is obtained as a result of illegal government activities.
Evidence that is collected by the government illegally will not be admitted into court. This has been tested in
court during the cases of Silverthorne Lumber Company v. United States, 251 U.S. 385 (1920) and Nardone v.
United States, 308 U.S. 338 (1939). If the accused person can establish a reasonable possibility that the evidence