Odin, a police dog, scratches at the gas tank door of a vehicle as New Jersey State Police trooper Chris Pastor works with his dog during a training exercise at the New Jersey Department of Public Works, Tuesday, Jan. 29, 2013, in Jersey City, N.J. Officers from various agencies are participating in the police dog class, which graduates on Feb. 8. (AP Photo/Julio Cortez)

By JESSE J. HOLLAND, The ASSOCIATED PRESS

WASHINGTON — Police don't have to extensively document and log the work of drug-sniffing dogs in the field to be able to use the results of their work in court, the Supreme Court ruled on Tuesday.

Instead, Justice Elena Kagan wrote for a unanimous court, courts should apply the same tests to dog sniffs they do when they look at other issues of whether police have probable cause to take an action.

"The question - similar to every inquiry into probable cause – is whether all the facts surrounding a 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," Kagan said. "A sniff is up to snuff when it meets that test."

The court's ruling overturns a decision by the Florida Supreme Court in the case of Aldo, a drug-sniffing police dog used by the Liberty County sheriff.

Aldo was trained to detect methamphetamine, marijuana, cocaine, heroin and ecstasy, and alerted his officer to the scent of drugs on a truck during a 2006 traffic stop.

Instead of those drugs, a search of Clayton Harris' truck resulted in 200 loose pseudoephedrine pills, 8,000 matches, a bottle of hydrochloric acid, two containers of antifreeze and a coffee filter full of iodine crystals – all ingredients for making methamphetamine. Harris was arrested and charged with possessing pseudoephedrine for use in manufacturing methamphetamine. Two months later, Harris was stopped again. Aldo again alerted his officer to the presence of drugs, but none were found.

Harris asked the courts to throw out evidence showing drugs were found in his truck, saying Aldo's alert did not give police probable cause for a search.

The Florida justices agreed, saying the police officer lacked probable cause to search, arguing that the officials' contention that a drug dog has been trained and certified to detect narcotics was not enough to establish the dog's reliability in court. Instead, the Florida court said, police needed to present training and certification records, field performance records, explanation of those records, and evidence concerning the dog handler's experience and training.

Kagan said that went too far. "A finding of a drug-detection dog's reliability cannot depend on the state's satisfaction of multiple, independent evidentiary requirements," she said. "No more for dogs than for human informants is such an inflexible checklist the way to prove reliability, and thus establish probable cause."

Instead of depending on police performance logs – "Errors may abound in such records," Kagan noted – standard training and certification records from the dog's training are much more reliable, she said.

"The better measure of a dog's reliability thus comes away from the field, in controlled testing environments," she said. "For that reason, evidence of a dog's satisfactory performance in a certification or training program can itself provide sufficient reason to trust his alert."

Defendants can challenge that evidence, Kagan said, by asserting for example that the training was too lax or the certification methods faulty. But "if the state has produced proof from controlled settings that a dog performs reliably in detecting drugs, and the defendant has not contested that showing, then the court should find probable cause," she said.

The Supreme Court has yet to decide a second question about police use of drug sniffing dogs, over whether they can bring their narcotic-detecting dogs to sniff around the outside of homes without a warrant. That decision is expected to come later this year.