WATCH | Some studies have found that on average, dogs give false positive alerts 80% of the time. This means that a police dog is more likely to be wrong than right.
In 2014, 24-year-old Charles Clarke was flying back to college with his life savings of $11,000 in his luggage. He said his bank didn't have branches close to campus so he decided to keep the cash on him.
Clarke was making his way through Cincinnati/Northern Kentucky Airport when a drug-sniffing dog detected something in his bag. Nothing was found.
Police searched Clarke's bag and seized the $11,000 even though there were no drugs or contraband. It was confiscated under civil asset forfeiture.
Civil asset forfeiture
Civil asset forfeiture allows law enforcement to take your property without having to charge you with a crime. It was now up to Clarke to prove his innocence.
The fight in court lasted over a year, but he eventually got his money back.
Florida v. Harris
In 2013, the Supreme Court heard Florida v. Harris, centering on the reliability of police dogs.
It addressed how some studies find that, on average, dogs give false positive alerts 80% of the time. This means that a police dog is more likely to be wrong than right.
Ultimately, the Supreme Court decided that as long as a police dog has a certification, an alert constitutes probable cause regardless of the K9's reliability at detecting illegal substances.
"All the police need is to achieve a positive dog alert and then your property is gone whether it's money or your car," said Darpana Sheth of the Institute for Justice.
Police dogs can be trained to detect trace amounts of drugs and explosives. But dogs aren't foolproof. Dogs can respond to subconscious human cues which can result in false alerts.
A 2011 study by researchers at the University of California at Davis found that K9s gave false alerts more than 200 times. Another study by the Chicago Tribune found that 66% of dog alerts were false positives. But advocates for the use of drug dogs say the statistics are inflated because a person might have had drugs on them at an earlier point which could trigger a false alert.
Chief William Brooks from Norwood, Massachusetts, pictured here, says that "when police seize money, it's because there are indications of drug activity even if they don't have enough evidence to bring a criminal charge."
WATCH | To learn more about civil asset forfeiture, check out Circa's documentary "SEIZED."
WATCH | An extreme case of how serious a false alert can become: Timothy Young said he was X-rayed and subjected to a cavity search. Nothing was found.