DENVER (AP) — A dozen people have been arrested in a Front Range sex trafficking ring that involved minors whose services were advertised on an Internet classified ad site.

Colorado Attorney General John Suthers announced Monday that four of those arrested are accused of paying to have sex with underage girls. Suthers says three people accused of offering juvenile girls up for sex on a community classified advertisement site,  are self-described members of the Crips gang.

The girls are receiving treatment at undisclosed locations.

Suthers says the sex trafficking ring operated in Denver, Aurora, Commerce City, Lakewood, Parker and Colorado Springs.

The FBI led Rocky Mountain Safe Streets Task Force's Innocence Lost Task Force investigated the case. Member agencies include Denver and Aurora police departments, and the Arapahoe County Sheriff's Office.

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