MARY LOUISE KELLY, HOST:

Marijuana is illegal in North Carolina, but police there are struggling with enforcement. That is because new smokable hemp products are popular and legal. Steve Harrison from member station WFAE reports that a recent violent arrest for marijuana possession illustrates the problem.

STEVE HARRISON, BYLINE: When police in Charlotte say they saw Anthony Lee and Christina Pierre smoking marijuana at a bus stop recently, they arrested them. A bystander filmed Pierre resisting arrest and fighting with the police. One officer repeatedly punched her in the leg, and she was hit at least once in the face.

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HARRISON: But in this case, there's a twist. Pierre's attorney, Lauren Newton, says her client wasn't even smoking pot.

LAUREN NEWTON: When the two officers walked up and asked what they were smoking, my client held up the THCA cigarette that she purchased from a local smoke shop in Charlotte.

HARRISON: THCA is a new cannabis product. When burned, through smoking, for instance, THCA converts to Delta-9 THC, the active ingredient in marijuana that gets people high. Newton says it's completely legal for her client to smoke it in North Carolina.

NEWTON: And it was almost as though the police were unwilling to believe her.

HARRISON: THCA cigarettes represent a new headache for law enforcement in numerous states where marijuana is still illegal. This legal strain of hemp has become popular in the last year and is now sold in stores across North Carolina as well as other often-conservative states, like Georgia, Florida and Texas.

PHIL DIXON: Legal cannabis products and illegal marijuana are not distinguishable by sight or smell.

HARRISON: That's Phil Dixon with UNC School of Government, who says what happened in Charlotte will continue to be a problem across the nation, and he says police should not use just smell to take action.

DIXON: It can't be probable cause to search or arrest somebody if that's all you have because there are so many of these legal products that look and smell just like it.

HARRISON: That's one reason why Charlotte City Council member Braxton Winston says he doesn't think police should attempt to control marijuana at all, especially in this case, where there's a small difference between THCA and traditional THC.

BRAXTON WINSTON: It's very hard, when you have to criminalize based on molecular structures, for municipal police forces to actually enforce that.

HARRISON: Charlotte police in recent years have looked the other way on many minor infractions, like public drinking, public urination and smoking marijuana in public. But some Charlotte residents say that's gone too far and are pushing police to enforce quality-of-life infractions. City Councilmember Ed Driggs says he supports more enforcement, but he doesn't know what to do about legal cannabis.

ED DRIGGS: It does raise a real problem in the sense of a disconnect between the letter of the law and the practical reality - they can't attack every instance of this, it's arguably legal, and so on.

HARRISON: The Mecklenburg County District Attorney announced last week that, after reviewing police body camera footage, it's dropping all charges against the two people arrested.

For NPR News, I'm Steve Harrison in Charlotte. Transcript provided by NPR, Copyright NPR.

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