In Katz, Federal Bureau of Investigation (FBI) agents suspected a public telephone was being used to transmit illegal gambling information. Without a search warrant, FBI agents placed an electronic listening device on the outside of the phone booth. Katz was convicted after the trial court determined the taped conversations were admissible. The U.S. Supreme Court reversed the conviction, ruling that the right to privacy had been violated because Katz had not knowingly exposed his telephone conversations to the public. In reaching its decision, the Supreme Court developed a two-part test: (1) that an individual must exhibit an actual, subjective expectation of privacy; and (2) that the expectation must be one that society is prepared to recognize as reasonable. The Supreme Court thus shifted the fourth amendment focus from the search of a constitutionally protected area to whether police intrusion violates an individual's reasonable expectation of privacy. When an individual closes the door of his or her home, the interior of the home becomes constitutionally protected and subject to the two-part test outlined in Katz. To safeguard this protection, a police officer is required to knock and announce prior to entry. Further, the fourth amendment requires a police officer to secure a valid search or arrest warrant before employing ruse. Ruse entries substantially decrease the threat of violent confrontation and reduce the risk of injury to police, home occupants, and innocent bystanders. Ruse entries also benefit society by allowing police to secure evidence before an occupant has a chance to destroy it. If ruse entries are employed correctly, fourth amendment protections which the knock and announce rule is designed to provide are still extended to the home occupant. Ruse does not require occupants to give up their reasonable expectation of privacy; only the issuance of a warrant by the court determines when an individual's privacy is surrendered. 122 footnotes