Two Florida cases involving drug-sniffing dogs will test the limits of the 4th Amendment at the Supreme Court this week.


The justices will rule on whether police conducted an unreasonable search when they acted on an anonymous tip and deployed a drug-sniffing Labrador retriever to Joelis Jardines’ Miami home in 2011. When the dog signaled the presence of drugs, police obtained a warrant, searched the home and found marijuana.


But although neither the dog nor the police entered the house, the Florida Supreme Court decided that the search was illegal. Since 1967, the court has recognized that searches don’t always involve physical trespass.


The state argued that no search occurred because the dog was outside the house and detected drugs from the outside air, but the court rejected the distinction, stating that what mattered was that the dog was detecting something inside the house.


It’s expected that a 2001 ruling on thermal imaging will feature prominently in opening arguments. In that case, the court decided that federal agents violated the 4th Amendment when they used a thermal imaging device to determine if a building was generating heat associated with growing marijuana.


The second case the Supreme Court will consider looks at how well drug-sniffing dogs are trained and how reliable they are.


In 2006, a Florida police officer pulled over a vehicle because it had an expired license plate, and the officer’s chocolate Labrador signaled that he detected the presence of chemicals used in methamphetamine production. The officer discovered drug-making materials in the vehicle and arrested Clayton Harris.


Weeks later, the same officer pulled Harris over again for a faulty brake light, and the dog again signaled the presence of drugs. This time, no illegal materials were found, and when the case went to trial, the Florida Supreme Court ruled the dog unreliable and ordered that the evidence be suppressed.


In 2005, Justice John Paul Stevens said that drug-sniffing dogs don’t invade privacy because their noses reveal "no information other than the location of a substance that no individual has any right to possess." However, in a dissent from that decision, Justice David H. Souter referenced a study showing "that dogs in artificial testing situations return false positives anywhere from 12.5 to 60 percent of the time."


Last year, an analysis by The Chicago Tribune revealed that illegal substances or drug paraphernalia were found just 44 percent of the time when drug-sniffing dogs signaled their handlers during roadside encounters.


However, prosecutors argue that the drugs could be well hidden or that the dogs could simply be detecting the lingering odor of drugs that are no longer in the vehicle.


"When you enter the kitchen and smell popcorn, the fact that some has already eaten all the popcorn and put the bag outside in the trash takes nothing away from the fact that you accurately smelled popcorn in the kitchen," attorneys wrote in the Harris case.


Further complicating the matter is that drug-sniffing dogs are trained to detect not drugs, but the smell of certain molecules within drugs. Because of this, dogs might alert handlers to the presence of a molecule in an innocuous substance.


For example, cocaine shares molecules with snapdragons and petunias and heroin shares one with vinegar.


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Laura Moss writes about a variety of topics with a focus on animals, science, language and culture. But she mostly writes about cats.

Supreme Court hears drug-sniffing dog cases
Two Florida cases involving drug-sniffing dogs will test the limits of the 4th Amendment at the Supreme Court this week.