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Whitesboro, Texas (CNN) -- It can be an odd feeling, returning to a place you once lived. Odder still, when that place belonged to the man who trafficked you across continents.
"I don't have any happy memories of this place at all," said Mophat Chongo, 26.
Chongo and his younger cousin, Given Kachepa, were brought to the unassuming tract of land in Whitesboro, Texas, in 1998 by Keith Grimes, who ran a high-profile, faith-based endeavor called TTT: Partners in Education.
Chongo and Kachepa were part of a 12-member a cappella boys' choir he'd brought over from Zambia to sing in front of audiences around the country.
In exchange, TTT promised to provide the boys a chance to earn money for themselves and to send it back to their families. They would also receive what is considered a coveted prize in many parts of the world: a U.S.-style education.
Kachepa said: "They said you're coming to the United States so that you can have this great opportunity to go to school, then we're also going to be building schools back home in your country.
"So we were excited about that opportunity. Not only for us, but for our brothers and sisters back home in Zambia."
But according to federal investigators, those promises were never kept.
The boys sang in churches, schools and shopping malls for more than a year. Often, they performed several concerts a day.
One budget statement from TTT: Partners in Education, obtained by CNN, showed the organization took in more than $1 million from performances, sponsorships, and donations, in just one year.
Despite this, Chongo says none of the boys were paid and they didn't go to school.
"We were out from five in the morning to 10 p.m. or midnight, performing all over the place. Sometimes we'd perform five concerts in a day. Sleep a little bit, perform everyday and then go to sleep again. We never enjoyed anything else and we were not introduced to an American life. We were kept or confined to the schedule."
Eventually, federal investigators became suspicious about the charity. Tips from concerned host families and interviews with choir members led agents to remove the choir members from the home.
"This was not a case of we're upset we want to go home," says Sal Orrantia, the immigration agent called to the scene. "They were brought here for a specific purpose and that was to get as much out of them -- with no regard for them or their futures."
Orrantia removed the members of the choir from Grimes' custody, but was concerned they would have to spend a night in juvenile detention, so he began looking for other options.
He called Colleyville Baptist Church and asked to meet with Sandy Shepherd, a former TTT volunteer, who had previously complained to federal authorities about the treatment the boys were receiving.
Shepherd said: "I got a phone call from one of the members of the church who said Immigration has just called the pastor and said that he has seven boys that he's just picked up from Whitesboro, and he doesn't have any place to put them and he wants to know if he can house them here."
Shepherd agreed and went on to help many of the boys find foster families. Some returned to Zambia. When she couldn't find Kachepa a permanent home, she took him into hers, where he's been ever since.
"To me, he's just like my other children. He's the son that God never gave me before and he's the son God brought into my life after the three daughters."
Since their rescue, both Chongo and Kachepa have gone from strength to strength. They both graduated high school and received college degrees.
Chongo, with a double masters in international banking and international finance, now has ambitions to work with organizations such as the World Bank or International Moneteary Fund.
And the school once promised by Grimes has been built thanks to Shepherd and church fundraising -- and is expanding. Earlier this year a new science block was opened.
"The school was started for the boys who went back to Zambia. As they graduated their siblings began to go to the school. My dream is to buy the property next door for two new classrooms and a library-computer lab," Shepherd said.
John Chakwin Jr., Special Agent in Charge of the ICE Office of Investigations in Dallas, says human trafficking is increasingly becoming a major problem across the United States.
According to the U.S. Department of State, as many as 17,500 people a year are trafficked into the United States from around the world.
In September, ICE's Dallas field office announced a new regional task force to identify and prosecute human traffickers, while also protecting and aiding their victims.
"If you go to a restaurant and you believe a person there is being forced to work there to pay off a debt, or you see a house down the street that has a lot of people living in it and they're not allowed to talk to anybody, they're not allowed to speak on the telephone, please bring it to our attention. Report it, don't walk away. Let us take a look," Chakwin Jr. said.
Keith Grimes was the subject of a criminal investigation, but the investigation ended when he died of natural causes. In 2001, the U.S. Department of Labor ruled TTT: Partners in Education was liable for $966,422.00 in back wages and civil money penalties for the members of the choir.
To date, no choir member has received a penny.
A statement from the Department of Labor to CNN said: "The U.S. Treasury was unsuccessful in securing back wages for these employees because the employer had died and his company was bankrupt."
More than a decade later, as Chongo and Kachepa walk the gravel road leading up Grimes' property, nervous apprehension and memories of their shared experiences, slow their gait.
Chongo had not been back since federal immigration agents removed the choir members. He paused before the barbed wire fence as emotions overwhelmed him.
"I was inside, and I never thought I could get out. And I look at it from the outside today, and you know, and I did so much to be outside."
He added: "There were times I did not know where I was going to end up. I just took a leap of faith."