Inside the Lives of American Sex Slaves

July 25, 2013— -- An undercover investigation for National Geographic explored the prevalence of sex trafficking within the United States, where the business of sexual slavery is booming.

When some people hear about sex trafficking in America they usually think of Asian and Eastern European women being brought into the States, but it's actually 10 times more likely for an American girl to be trafficked inside the U.S. Further, almost 300,000 American children are at risk for trafficking into the sex industry, according to U.S. Department of State statistics.

For National Geographic's "Inside: Secret America" series, investigative journalist Mariana van Zeller, who is now a correspondent for Fusion, an ABC News joint venture with Univision, and her producers Darren Foster and Alex Simmons went undercover on the streets of Houston to get a first-hand glimpse inside the world of sex trafficking. The "American Sex Slave" episode aired on Wednesday at 10 p.m. on the National Geographic Channel.

During the investigation, a man who had been in the lobby of a massage parlor at a strip mall waved van Zeller over to his car. The man told her he was a lawyer and the spa was known around town as a place where men can pay $200 to get the "full service." He then offered van Zeller money and said if she "took care" of him, then he would "take care" of her.

"This guy told me that if I worked five guys a day that I could make $1,000 a day, and it was pretty good," van Zeller told her team after she walked away.

When van Zeller looked up the man later that evening, she said she found he does have a professional job and did not find evidence he was a pimp.

However, during the course of her investigation, van Zeller learned about the wide range of pimps. She sat down with sex trafficking victim Jillian Mourning. Growing up as the quintessential girl-next-door, Mourning was a high school cheerleader and a straight-A student. As a 19-year-old college freshman, she said she became a part-time model.

But while on one job in Scottsdale, Ariz., Mourning told van Zeller that three men entered her hotel room in the middle of the night. One of them was a man in the modeling industry.

"And they all raped me, and they videotaped it and photographed it," Mourning said.

When she returned home to Charlotte, N.C., Mourning told van Zeller that she was too embarrassed to tell her friends what had happened to her and too afraid to go to the police. She decided to put the incident behind her, but then she said her abuser called.

"He wanted me to meet these men and sleep with them, and he gets all the footage," Mourning said. "And I was like, 'I'm not comfortable with that." and then he said, "well, you know, in other words, if I'm not going to be able to get you to do this voluntarily, then you're still going to do it.'"

Mourning told van Zeller that her abuser claimed he had the videos of her being raped in Arizona and he threatened to sell them on the Internet with her name attached to them if she didn't prostitute for him.

"It became threat after threat after blackmail after blackmail," Mourning said. "So when he went to say, 'hey, you know, I need you to go to this city,' or 'I'm in Charlotte and I need you to meet with this person,' then I did."

Mourning said her trafficker was a wealthy and respected member of the Charlotte community, not someone who would have been suspected of sex trafficking.