Is a Dog-Sniff Alert Sufficient to Establish Probable Cause?

On October 31st, 2012, while the rest of the country will be busy celebrating Halloween, the Supreme Court of the United States (SCOTUS) will face the haunting and controversial question of whether a dog-sniff alert is sufficient for establishing probable cause.  The two cases, both out of Florida, touch on one of a myriad of issues that must be resolved as SCOTUS defines the contours of our Fourth Amendment rights.  The impact of the court’s ruling will have reverberations and consequences on the law enforcement community and criminal trials for years to come.

Florida v. Harris[1]

In the first case, Clayton Harris was driving with an expired tag, according to Deputy Wheetley.  Following a valid stop, Deputy Wheetley noticed Harris acting visible nervous.  Moreover, there was an open container of alcohol in the cup holder.  Harris denied the Deputy’s request to search the vehicle.  The Deputy retrieved a K-9 narcotics detection dog.  The K-9 sniffed the car and alerted Deputy Wheetley of narcotics.

Harris was asked to exit the vehicle while a search of the vehicle was conducted.  The search yielded narcotics and other contraband.

The trial court denied the Defendant’s motion to suppress and found there was probable cause to search.  The First District Court of Appeal affirmed.  The Supreme Court of Florida reversed the opinion of the First District.  The United States Supreme Court granted certiorari to the State of Florida to review the judgment of the Supreme Court of Florida.

Florida v. Jardines

In Jardines, Florida law enforcement officials received a tip that the defendant was growing marijuana inside his home.  They then brought a drug dog to the defendant’s home, and after the dog indicated that there was marijuana inside, the police entered and found the plants.  The Florida Supreme Court held that the use of the dog without a warrant violated the defendant’s Fourth Amendment rights and even if a drug dog alerts the police that there are narcotics inside, a warrant is still required.  The rationale behind the Florida Supreme Court’s ruling was that if law enforcement officials are able to conduct a test such as this without any prior showing of wrongdoing, there is nothing to prevent the officials from doing this at any civilian’s home based on little to no evidence.


Under the Fourth Amendment:

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

SCOTUS has previously ruled that a dog sniff in and of itself is not a search, based largely on its non-intrusive nature[2]. In Florida v. Harris, the dog sniff was not the search; it was, however, the basis for probable cause justifying the vehicle search.  The Supreme Court of Florida held that evidence of a K-9’s training, qualifications, and certifications are insufficient to establish the dog’s reliability to determine probable cause.

Other federal courts weighing in on this issue has determined that an alert by a well-trained narcotics detection dog does, in fact, provide probable cause.[3]

Should Florida v. Harris be upheld, will that invite more challenges to K-9s used to track felons and detect explosives?  Will this limit the usefulness of dogs in a law enforcement capacity?

Massachusetts treatment of the issue

Massachusetts has held that a dog sniff will usually suffice as the basis of probable cause[4]. However, when the dog is the sole basis of the search under the “totality of the circumstances” test, the government must show why the particular dog was reliable.  This determination focuses heavily upon the dog’s qualifications: certifications, training, experience, and success rate.

Infallible dog theory

In a dissenting opinion regarding a dog-sniffing case, Justice Souter once quipped: “The infallible dog, however, is a creature of legal fiction.”[5] He went on to describe the error rates of dogs and their limited reliability.  Indeed, despite their usefulness, there are numerous issues when law enforcement officials rely too heavily upon a dog sniff.  The first is the dog’s qualifications, their training, success rates, etc.  A second consideration is the role of the handler.  How qualified is that handler?  How well do they understand the dog they are handling?  Finally, what was the alert the dog gave – passive or aggressive?  Was it interpreted properly?

The role of dog sniffs in the context of Fourth Amendment rights continues to evolve.  Florida v. Harris will be a seminal case in Fourth Amendment jurisprudence and will undoubtedly affect judges, attorneys, and law enforcement officials moving forward.

Editor’s Note – Updated on October 31, 2012.


[2]United States v. Place, 462 U.S. 696, 706-07 ( 1983).

[3] U.S. v. Sentovich, 677 F.2d 834 (11th Cir. 1982); U.S. v. Robinson, 390 F.3d 853 (6th Cir. 2004); U.S. v. Parada, 577 F.3d 1275, 1282 (10th Cir. 2009).

[4] Commonwealth v. Matias, 440 Mass 787, 793 (2003).

[5]Illinois v. Caballes, 543 US 405, 412 (2005).

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