Marijuana is in a hazy spot in Texas, legally speaking.

It's illegal, sure, but law enforcement has more or less been defanged when it comes to enforcing that ban on pot in the Texas Criminal Code. Since last summer, when its cousin hemp was legalized, officials have had to prove suspected marijuana is actual marijuana. That is, it contains a specific amount of THC – the psychoactive ingredient in pot. Because testing is cost-prohibitive, many counties effectively stopped prosecuting people for low-level possession.

Now, researchers from Texas A&M say they've found a cheap, accurate method for cops to discern whether seized material is illegal.

In a study released last month, Texas AgriLife researchers Dmitry Kurouski and Lee Sanchez touted their new testing method as a way for law enforcement to determine whether a substance is pot or hemp – by using lasers.

Put simply, a laser from a spectrometer hits a substance and then maps it out on graph. A substance without THC maps differently than one that contains it, providing a near-instant readout of whether a substance violates the state ban on substances with more than 0.3%-concentration of THC or whether it's legal hemp.

Kurouski says the device, which is about the size of a lunchbox, could be used by law enforcement with astounding accuracy during traffic stops or at crime scenes.

"The accuracy is 100%," he said. "[Meaning] we can differentiate between hemp and cannabis, and that's really remarkable."

Kurouski says the scanner could also identify different strains of cannabis.

The device could help hemp-growers who may be hassled by law enforcement, he said, citing an Amarillo case in which a man was arrested for hauling marijuana then was let go when his cargo proved to be hemp in lab tests.

Still, Kurouski's scanner wouldn't meet the immediate need for a quick turnaround on evidence tests. He estimates it would take roughly two to three years to mass-produce.

Jurisdictions throughout Texas stopped pursuing low-level marijuana cases after House Bill 1325, which sought to establish a regulatory framework for the budding hemp industry, went into effect. Over the objections of the state's top lawmakers, county attorneys in Travis, Bexar, Harris and Tarrant counties said last summer they won't prosecute low-level cases until they can find a cheaper, more expedient way to test evidence. Texas Department of Public Safety troopers have been told not to arrest people suspected of possession of marijuana.

In Austin, city leaders effectively decriminalized low-level marijuana possession cases last month when they asked Austin police to stop citing people. Austin Police Chief Brian Manley has said, however, his officers will continue to cite and arrest people accused of possession.

Got a tip? Email Andrew Weber at aweber@kut.org. Follow him on Twitter @England_Weber.

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