When Probable Cause Looks More Like 'Meh, Maybe?' Cause

On April 20, 2012, deputies from the Johnson County, Kansas, sheriff's department stormed the home of Robert and Adlynn Harte, apparently expecting to uncover a marijuana grow operation. It was, after all, 4/20.

What they found instead was an indoor garden in the basement, a project the Hartes had started with their two young children to grow tomato, squash and melon plants. The legal battle touched off by the dangerous mistake ended last week  in a ruling that exposes just how weak the standard of "probable cause" can be.

At first, the Hartes, both former CIA employees, couldn't understand what had led police to believe they were involved in the drug trade. They spent $25,000 in a quest to access the probable-cause affidavits used to obtain the search warrants for their home. Kansas didn't release those documents to the public until the law was changed  last year, with lobbying help from the Hartes.

When they read the flimsy evidence that had prompted the botched raid, the Hartes were outraged.

The initial tipoff to police had come in 2011, when a Missouri state trooper witnessed Robert Harte exiting a gardening store with a bag of supplies. Many such businesses in Kansas and Missouri were staked out over 2011 and 2012 as part of a controversial anti-drug effort called "Operation Constant Gardener ."

Police then worked to gather more evidence against the Hartes, and months after the initial tip, they believed they'd found it hiding at the bottom of the family's trash. Officers dug up a wet, leafy green material from two separate garbage bags that the family had left out on the curb. One deputy would state that based on his experience, it looked as though the substance had been processed through the "extraction of ... THC," according to a civil rights complaint  filed by the Hartes in 2013. Police conducted a field test on the material, and shortly after it tested positive for marijuana, the raid was green-lighted.

But field testing for drugs is notoriously unreliable .

In their lawsuit, the Hartes argued that using dubious drug tests to build upon a single additional piece of dubious evidence -- a trip to a garden store, no less -- shouldn't be enough to launch a police raid. But a federal judge ruled last Friday that no constitutional violations had occurred and the officers had sufficient probable cause for the search.

The judge was apparently not moved by the Hartes' argument that field drug tests are notoriously unreliable and that field testing the substance found in their trash -- tea leaves, according to the Hartes -- would have been even less likely to produce accurate results.

"The deputy did not acknowledge in the affidavit that the field tests are not to be used with saturated or liquid samples and that the 'false positive' rate of the test used is 70 percent," the Hartes' complaint read. "Many common botanical substances from the kitchen or yard also test positive [for the presence of marijuana], including vanilla, anise, peppermint, ginseng, eucalyptus, cinnamon, basil, lemon grass, lavender, cloves, cypress, ginger, oregano -- and tea."

Lab tests conducted after the raid concluded that the material in the Hartes' trash was indeed not marijuana, nor did it "look anything" like the plant. The Johnson County sheriff's office now requires lab confirmation of suspected drug material , so perhaps there's one small victory to come out of the Hartes' misfortune.

The Hartes also argued that police displayed "excessive" force during the raid, opting to use a "heavily armed SWAT-type team" and even accusing their son, then 13, of having a "drug problem." But the judge found that the officers had conducted themselves in a lawful and reasonable manner.

The Hartes were seeking $5 million in compensatory damages and $2 million in punitive damages for violations of their Fourth and 14th Amendment rights.

The Fourth Amendment to the Constitution states that search warrants may be issued only "upon probable cause." Over at Reason, Jacob Sullum neatly sums up  why probable cause often rests on improbable evidence:

[T]he Supreme Court has said it need amount to no more than a "substantial chance" or a "fair probability" that evidence of a crime will be discovered. It's clear that a probability substantially lower than 50 percent will do, which is why courts continue to treat highly unreliable indicators such as drug field tests and dog alerts as sufficient to justify a search .

The Hartes' case also offers another sad commentary on the ineffectiveness of the drug war. If we're going to pay police to enforce draconian marijuana laws at all, we should at least hire officers who can tell the difference between marijuana and wet tea leaves -- or okra, tomatoes, elderberries, hibiscus and ragweed, all plants that police have managed to mistake for marijuana .

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