The US Supreme Court said Monday it will decide whether it is necessary to provide detailed documentation of drug dog's reliability to prove that the dog is effective at finding drugs. The high court accepted a case on appeal from the state of Florida.

The Florida Supreme Court threw out evidence derived from a drug dog search, holding that police and prosecutors had not provided sufficient evidence of a drug dog's reliability and thus had not provided probable cause to undertake the search.

The case in question, Harris v. Florida, began with a pair of drug dog sniffs of a vehicle being driven by Clayton Harris in Liberty County, between Panama City and Tallahassee in 2006. In the first search, the drug dog alerted and police found pseudoephedrine and other meth-making materials. In the second sniff, the drug dog alerted, but no drugs were found.

As is common practice in Florida and many other states, at trial, prosecutors merely presented evidence that the dog and been trained and certified at drug detection. But on hearing Harris's appeal, the Florida Supreme Court ruled that wasn't good enough.

"Like the informant whose information forms the basis for probable cause, where the dog's alert is the linchpin of the probable cause analysis, such as in this case, the reliability of the dog to alert to illegal substances within the vehicle is crucial to determining whether probable cause exists," the court held. "We conclude that when a dog alerts, the fact that the dog has been trained and certified is simply not enough to establish probable cause to search the interior of the vehicle and the person."

The state's presentation of evidence that the dog is properly trained is just the beginning -- not the end -- of whether probable cause has been shown, the court said.

"Because there is no uniform standard for training and certification of drug-detection dogs, the State must explain the training and certification so that the trial court can evaluate how well the dog is trained and whether the dog falsely alerts in training (and, if so, the percentage of false alerts)," the court held in Harris.

"Further, the State should keep and present records of the dog's performance in the field, including the dog's successes (alerts where contraband that the dog was trained to detect was found) and failures ("unverified" alerts where no contraband that the dog was trained to detect was found). The State then has the opportunity to present evidence explaining the significance of any unverified alerts, as well as the dog's ability to detect or distinguish residual odors. Finally, the State must present evidence of the experience and training of the officer handling the dog. Under a totality of the circumstances analysis, the court can then consider all of the presented evidence and evaluate the dog’s reliability."

The US Supreme Court decision will be awaited with great interest by law enforcement, which has found drug dogs a very useful tool in going after drug offenders, especially since the Supreme Court has earlier ruled that a drug dog sniff is not a "search" under the meaning of the Fourth Amendment. The National Police Canine Association has filed a friend of the court brief in the case.

This is the second Florida drug dog case the high court will examine this year. In January, it said it would decide whether a drug dog sniff of the front door of a residence violates the Fourth Amendment. While it has okayed drug dog sniffs at traffic stops, at airport luggage inspections, and for shipped packages in transit, it has repeatedly emphasized that a residence is entitled to greater privacy than cars on a highway.

That case should have oral arguments next month and a decision in September. It is not yet clear when Harris v. Florida will be heard.