A Sheriff’s deputy and his drug-detecting K-9 companion in (the ironically named) Liberty County, Florida pulled over William Harris for a routine traffic stop. Observing Harris’s nervousness and an open beer can, the deputy (Wheatley) asked for permission from Harris to search Harris’ vehicle.   Harris refused to consent to the search, so the deputy retrieved his K-9, Aldo, to sniff around the exterior of Harris’ vehicle. The dog alerted at the driver’s-side door handle, so Wheatley concluded that he had probable cause for a search of the vehicle. That search turned up nothing Aldo was trained to detect, but did reveal multiple items that were consistent with manufacturing methamphetamine.   Harris was arrested for possession of those items.

While awaiting resolution of those charges, Wheatley again encountered Harris, pulled him over (for a tail light violation), and Aldo again alerted on Harris’ truck, but nothing was found.

Harris moved to suppress the evidence found in the course of the first search, focusing on Aldo’s certification and performance in the field, particularly in the two stops of Harris’ truck. The trial court denied the motion to suppress, and the Florida Supreme Court reversed.   The Florida Supreme Court set forth what was in essence a checklist of specific evidence that would always be necessary to establish probable cause on the basis of a K-9 sniff.    Among other things, the Florida Supreme Court required production by the state of all field-performance records for the K-9, showing how many times the dog has falsely alerted. The Florida Supreme Court held that in the absence of such records (and other listed items regarding the K-9’s certification, training and field performance), there could never be probable cause to think a K-9’s detection was a sufficiently reliable indicator of drugs so as to support probable cause for a search.

In a unanimous opinion written by Justice Kagan, the United States Supreme Court reversed the Florida Supreme Court and broadly rejected the Florida Supreme Court’s checklist-style approach to determining probable cause in the context of a dog-sniff or otherwise.   The Supreme Court reiterated the concept that determining whether an officer has probable cause to conduct a search, all that is required is the kind of “fair probability” on which “reasonable and prudent [people] act.”    To evaluate whether the State has met this “practical” and “common-sensical” standard, courts have consistently looked to the ‘totality of the circumstances’ and have generally rejected rigid, bright-line tests, and “mechanistic inquiries.”

The court’s opinion in Harris went on to fault the Florida Supreme Court’s creation of a strict evidentiary checklist to assess Aldo’s reliability.    Requiring such a rigid, “mechanistic” inquiry “is the antithesis” of a totality-of-the-circumstances approach that is applicable to probable cause hearings.    To be sure, field records of the sort the Florida Supreme Court required may nevertheless be relevant, but courts should evaluate all of the evi ­dence rather than prescribe an inflexible set of requirements.   Under the correct approach, a probable-cause hearing should proceed like any other, and the question should be whether all of the evidence and facts surrounding the dog’s alert, viewed through the lens of common sense, would make a reasonably prudent person think that a search would reveal contraband or evidence of a crime.

This unanimous opinion will no doubt be cited as the controlling case regarding K-9 searches; in reality it merely laid down the rule that the basic probable cause inquiry should govern, regardless of whether a K-9 was involved in any particular case.

A copy of the Supreme Court’s full opinion can be found here.   The Florida Supreme Court’s case (that the US Supreme Court reversed) can be found here.