DENVER (AP) - Authorities say the black market for marijuana is alive and well in Colorado, despite it being the first state to legalize recreational sales of the drug.

Recent drug busts and violence have raised concerns among police, prosecutors and pot advocates. They also worry that because possession of up to an ounce is legal in Colorado, illegal dealers and sellers believe they are less vulnerable to prosecution.

Among the concerning cases is the January killing of 25-year-old Nathan Tallman. Police say he disappeared after going to meet a man for a “marijuana transaction.” Authorities found him dead of a gunshot wound more than a month later along a rural Wyoming highway.

Advocates say legalization needs more time to unfold before black market sales will dissipate.

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