Drug Dogs: Proof Not Required, Says Court

Drug dogs have had more than one day in court, but the U.S. Supreme Court had the final say on Tuesday. Jesse J. Holland reports in The San Francisco Chronicle that, by an unanimous decision written by Justice Elena Kagan, the high court ruled police officers don’t have to provide extensive proof of a dog’s skill to use the evidence they find in court.

“A sniff is up to snuff,” she said, when it meets the standard of probable cause. A police officer is allowed to use common sense when assessing whether a dog’s alert, combined with other observations, would encourage a reasonable person to conclude that a crime has been committed.

Richard Wolf, reporting for USA Today, had more details about why the case seemed worth taking to the highest court in the land. Glen Gifford, an assistant public defender for one of the accused in the disputed drug bust, says, “Dogs make mistakes.”

Aldo, the drug dog in question, has since been retired. Trained to sniff out common drugs of abuse, including marijuana, ecstasy, cocaine, methamphetamine, and heroin, Aldo was working a Florida traffic stop in 2006 when the German Shepherd alerted on a truck driven by Clayton Harris.

None of those drugs were found. However, Harris was holding a large quantity of the ingredients needed to produce methamphetamine. He was charged with possession of pseudoephedrine. The same dog alerted on his truck again two months later. This time, no drugs of any kind were found.

A reasonable person might conclude that the trained drug dog was no such thing. Instead of sniffing for drugs, Aldo may well have picked up subtle cues from his human handler that Harris seemed shady.

Animal trainers have been bedeviled by this problem, called the Clever Hans phenomena, for well over a century. Clever Hans was a horse who became a sensation in 1891 because he appeared to be able to count by tapping out the correct number on demand. As Benjamin Radford (no relation to this writer) noted in a report for Discovery, the trainer wasn’t participating in a deliberate hoax. Trained animals are very good at reading human body language, and Clever Hans was proved to be reading and then responding to his trainer’s unconscious cues.

However, the Supreme Court was unimpressed. Kagan wrote:

“Harris principally relied…on [Animal Officer] Wheetley’s
failure to find any substance that Aldo was trained to detect. That
infers too much from the failure of a particular alert to lead to drugs.”

You can read the entire decision on the U.S. Supreme Court’s official blog. The justices seem inclined to give the drug dogs the benefit of the doubt, even if they do make the occasional mistake.