A Dekalb County Police Department drug dog stands by a display of illegal drugs seized during 2013 at their headquarters in Tucker, Georgia.  (EPA/ERIK S. LESSER)

Over the last 20 years or so, the Supreme Court has repeatedly held that the alert from a drug dog is enough to establish probable cause for a search. The problem is that while it’s true that dogs have a finely tuned sense of smell, far better than any technology we humans have been able to develop, we’ve also bred into dogs a trait that can supersede that ability—an eagerness to please us.

Without careful training, drug dogs will end up relying more on the body language of their trainers than on their olfactory prowess. That means that for many drug dogs, an “alert” is little more than a validation of the suspicions of its handler, and the very purpose of the Fourth Amendment is to protect us from invasive searches based merely on the suspicions of an agent of the government. Controlled academic studies of K9 team performances, for example, have shown that tests designed to trick a drug dog’s handler are far more likely to make the dogs falsely alert than tests designed to trick the dogs themselves.

That’s why the field performance records of drug dogs are often no better—and sometimes worsethan a coin flip. Yet a dog’s alert during a traffic stop can result in a thorough search of your car, allowing police officers to snoop in all of your belongings. It can also give them cause to rip out upholstery and linings, damaging your car. (And in case you’re innocent, good luck getting compensated for it.) Worse, an alert, combined with a few hard-to-prove allegations from a cop about your body language or “suspicious” answers to questions, can result in the seizure and forfeiture of any cash or valuables you happen to be carrying, even if the officer doesn’t actually find a measurable quantity of drugs.

One of the more notorious parts of the country for this mess of targeted traffic stops, drug dogs and forfeiture are the eastern suburbs of St. Louis, the corridor around I-70 and I-64, including the Illinois towns of Collinsville, Maryville and Belleville. A couple years ago, I wrote about a particularly dubious stop in Collinsville of Terrance Huff, who also happens to be a documentary filmmaker. Huff has since filed a lawsuit, and through discovery is finding out all sorts of interesting things about how drug dogs are used in this area, by both local and state police. (Huff’s story was also the inspiration for a recent episode of “The Good Wife.”)

I bring all of this up because of a story Huff recently sent me from the Belleville Democrat about a fundraising effort to purchase a new K9 for the Belleville Police Department.

Guilty, like many Belleville residents, has strong ties to Germany, where he was born and partially trained.

Residents might see the 128-pound Guilty searching for drugs, sniffing the trail of a bad guy on the loose, performing canine demonstrations or just out getting some exercise.

“He’s social. He’s almost like a jokester,” Dowdy described his partner. “He’s a little bull headed, like sometimes you have to motivate him to do things if he doesn’t feel like he wants to do them. He’ll just sit down and look at you sometimes.”

Dowdy, 40, is an animal lover who always wanted to train police dogs . . .

In December, after a retail theft was reported at Kmart, Guilty “ran a track” and located the suspect, Dowdy said.

Got that? They named the dog “Guilty.” Doesn’t inspire much confidence in the dog’s independence, does it? I suspect defense attorneys in the area have already made note of the dog’s name.

The article is short on details, but I’d also be curious to know how a police dog could be used to identify a shoplifting suspect. I suppose he could locate a person who had fled into a wooded area, in the sense that he could sniff out a person in an area where there are no other people around. But unless the suspect stole a bunch of meat, it seems dubious that a dog could track down a guilty shoplifter in a crowd. “Scent lineups”—in which police dogs “detect” the guilty party—are notoriously junky science.