The six were indicted Wednesday, The Denver Post reported.
Investigators say the victim, a 17-year-old from Colorado Springs, decided to run away after being suspended from school in May. She allegedly went to stay with Daivean Shields, 19, described as her ex-boyfriend.
Shields allegedly told the girl David Abney, 32, would show her how to make some money. Investigators say Abney took her to Denver with a 19-year-old named Cinnamon Toast O'Conner and Chrystal Terbush, 28, who allegedly prepared the two teens to sell their bodies.
"Terbush used her credit card and computer to post advertisements on backpage.com," the indictment said. "Terbush would post nude or semi-nude pictures of herself or other women and advertise their services as an escort, leaving a phone number for the johns to call."
Abney, Terbush, Shields and Tevin Willis, 19, face a long list of charges including kidnapping and trafficking children. The two alleged customers are charged with patronizing a child prostitute.