Rethinking Canine Sniffs: the Impact of Kyllo v. United States

JurisdictionUnited States,Federal
CitationVol. 26 No. 01
Publication year2002



Rethinking Canine Sniffs: The Impact of Kyllo v. United States

Amanda S. Froh(fn*)

I. Introduction

On October 26, 2001, the United States Congress hastily passed (and President Bush signed) legislation(fn1) that significantly expanded the tools available to law enforcement agencies to combat terrorism and gather intelligence domestically.(fn2) Concern about the impact of this new legislation on civil liberties inspired lawmakers to initiate a "sunset provision" that requires the bill to be reauthorized by 2005 in order for it to remain effective.(fn3) Senator Patrick Leahy (D-Vt), the Senate negotiator for the bill, reluctantly acquiesced to President Bush's demands for anti-terrorism powers that may infringe on the civil liberties of Americans.(fn4) Despite these reservations, both Congress and the American public appear willing to relinquish some personal privacy in times of war for the greater public interest.

Even when the nation is not at war, law enforcement personnel use surveillance and investigative technologies on a daily basis. The Supreme Court recently determined in a series of contradictory cases whether the use of certain law enforcement investigative devices are "searches" within the meaning of the Fourth Amendment. Two of these technologies are addressed in this Note: the use of heat-imaging technology and the use of drug-sniffing dogs.

In its 2000-01 term, the Supreme Court held in Kyllo v. United States that the use of a thermal imager is a "search" within the meaning of the Fourth Amendment.(fn5) A thermal imager is a device that detects infrared radiation and converts that radiation into images according to its relative warmth.(fn6) With the help of the thermal imager, the person operating the device can see images of objects and people inside a building that emit infrared radiation.(fn7) The use of this device was a search because a thermal imager was not available to the general public and was being used to gather details that could not have been known but for physical intrusion into the home.(fn8) Therefore, its use is presumptively unreasonable without a warrant.(fn9) During the same term, the Court reiterated, in dicta, in City of Indianapolis v. Edmond that the use of a drug-sniffing canine by law enforcement is not considered a search within the meaning of the Fourth Amendment.(fn10) Even though these two investigative tools are used to gather information that would otherwise not be available without physical invasion, the Court has concluded that while one is a search, the other is not.

This Note does not attempt to reconcile these seemingly contradictory conclusions. Instead, the following paragraphs argue that the Court's holding in Kyllo requires courts to rethink whether a canine sniff is a search or not within the meaning of the Fourth Amendment.

In 1983, the United States Supreme Court stated, in dicta, that a canine sniff of an object is not a search.(fn11) This conclusion was based largely on the limited nature of the intrusion of a dog sniff, both because of the manner in which the information is obtained and the type of information that is revealed.(fn12) The argument is that the canine sniff is so unintrusive that it could not infringe on an individual's expectation of privacy and therefore does not trigger the protections of the Fourth Amendment.(fn13)

With most other investigative techniques, the Court has considered four general factors unrelated to the characteristics of the search itself to determine if there is an expectation of privacy.(fn14) Although the thermal imager used in Kyllo had essentially the same characteristics as a canine sniff in terms of the nature of the intrusion, the Court considered the traditional four factors rather than the limited-nature factors. This Note argues that, in light of the reasoning in Kyllo, canine-sniff jurisprudence should be reexamined under the "expectation of privacy" framework, which this author argues requires examination of four factors, rather than the limited-nature framework, which examines the nature of the intrusion. Application of the expectation of privacy framework to dog sniffs would likely lead to a different finding: the use of a drug-sniffing dog is a search, though it could be a minimally intrusive one depending on the context.

The argument develops as follows. Part II provides a general background on how the court has determined whether an investigative technique or device is a search within the meaning of the Fourth Amendment, and the implications for finding that something is a search. This section focuses primarily on Katz v. United States, the pivotal case in which the Supreme Court departed from previous Fourth Amendment jurisprudence by recognizing that the Fourth Amendment's core value is the protection of individual privacy, not the protection of places.(fn15) In light of this background, Part III provides examples of how the Supreme Court has applied Katz to certain factual situations, and what factors it has traditionally considered to determine if a reasonable expectation of privacy exists. Part IV examines the reasoning of the Kyllo decision and evaluates it in terms of those traditional factors. Part V looks closely at the landmark case in canine sniffs, United States v. Place, and analyzes the Court's reasoning in finding that a dog sniff was not a search. Finally, Part VI explores how and why the reasoning in Place and other dog-sniff cases has been eroded by the Court's reasoning and holding in Kyllo.

II. When Is a Search Really a Search? Katz v. United States

The Fourth Amendment establishes the right of individuals to be "secure in their persons, houses, papers, and effects, against unreasonable searches and seizures."(fn16) Since its adoption, the question of when a Fourth Amendment search(fn17) has occurred has not been easily answered.(fn18) However, the implications for such a finding are significant.

Characterizing an action as a search is essentially a conclusion about whether the Fourth Amendment even applies.(fn19) Police tactics are not subject to judicial regulation unless deemed a search(fn20) (although techniques deemed not a search could still be regulated statutorily(fn21). Without judicial regulation, the police are free to use such methods at random, with little or no constitutional limit on their discretion.(fn22) Moreover, any evidence gathered in the course of such action would always be admissible in a criminal trial, unless excluded under some theory other than a Fourth Amendment violation.(fn23)

However, if an action is a search then it must satisfy the Fourth Amendment requirements: it must be reasonable; the officer must have probable cause; and the search may only be properly conducted when a warrant is obtained from a neutral magistrate, unless there are exigent circumstances.(fn24) Therefore, calling a police action a search within the meaning of the Fourth Amendment has implications for both the rights of the individual and the permissible actions of law enforcement officers.

Prior to Katz v. United States, arguments regarding whether a police tactic was a search centered on the common law idea of trespass.(fn25) Under this common law approach, a tactic was only a search if it was in the form of trespass on tangible property; an "invasion" was required to trigger Fourth Amendment protections.(fn26) The Katz Court rejected this traditional formulation.(fn27) In Katz, the Court reconceptu-alized the Fourth Amendment, turning the focus from the trespassory formulation to the core value that -p[the modern Fourth Amendment was intended to protect: individual privacy against certain kinds of governmental intrusion.(fn28) This is what Justice Stewart meant when he claimed that "the Fourth Amendment protects people, not places."(fn29)

In Katz, the Government attached an electronic eavesdropping device to the outside of a public telephone booth, which enabled the FBI to overhear the defendant's incriminating statements.(fn30) In the presentation of its case, the Government confidently advanced the traditional property-based rationale by arguing that use of the device was not a search because it merely detected and translated sound waves emanating from the phone booth.(fn31) Therefore, there was no physical penetration or trespass into the phone booth.(fn32)

The Court rejected this mechanical application.(fn33) Despite the prior cases equating Fourth Amendment protection to trespass, the Fourth Amendment does not protect anything a person knowingly exposes to the public, even in his own home or office.(fn34) By the same token, what a person seeks to preserve as private, even in a public area, may be constitutionally protected.(fn35)

According to the Katz Court, a person has a reasonable expectation of privacy when a person enters a phone booth, shuts the door behind him, and deposits the fee for the call.(fn36) And society recognizes this expectation of privacy as reasonable.(fn37) Given the defendant's reasonable privacy expectations, the Court found that the use of the eavesdropping device was an unconstitutional search, regardless of the fact that the phone booth was in a public area and had glass walls that exposed the caller further to the public eye.(fn38)

In his concurring opinion, Justice Harlan articulated the...

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