A decade ago, Shyima Hall was smuggled into the United States as a 10-year-old slave, forced to cook and clean inside the home of a wealthy Irvine family and, at night, sleep on a squalid mattress in a windowless garage.

On Thursday, the Egyptian-born 22-year-old stood before a federal judge in Montebello with nearly 900 others and was sworn in as naturalized U.S. citizen. The ceremony capped a hard-scrabble journey that began with Hall's rescue, wound through the foster care system and ended with her living on her own, working, and with ambitions to become a federal agent.

"I went through something terrible, but right now I'm in a great place," Hall said after Thursday's citizenship ceremony at the Quiet Cannon Country Club. "I can't imagine anything greater than having my own life."

Hall's Egyptian parents sold her into slavery when she was 8 for $30 a month, according to authorities. The Cairo couple who bought her moved to Irvine two years later, smuggling Hall into the U.S. where she toiled for them and their five children until she was 13.

Hall said she worked 16 hour days, scrubbing floors, cooking meals and cleaning house, and was rarely allowed outside the spacious home. She was forced to wash her own clothes in a bucket and was forbidden from going to school. She never visited a doctor or dentist and didn't speak a word of English.

Her captors, Abdel Nasser Eid Youssef Ibrahim and his former wife, Amal Ahmed Ewis-abd Motelib, berated her and occasionally slapped her around, authorities said.

"I didn't know anything about what America was about. My only hope was to go back home and live a normal life with my family, my brothers and sisters,'' she said. "That's all I wanted."

In 2002, acting on a tip from a concerned neighbor, child welfare authorities rescued her from the house. Her case was investigated by U.S. Immigration and Customs Enforcement, leading to the prosecution, federal imprisonment and, later, deportation of Ibrahim and Motelib.

Hall formed a tight bond with one of the lead federal agents, Mark Abend of ICE's Homeland Security Investigations, who has served as a friend and mentor. He was at Hall's citizenship ceremony Thursday.

"I'm really proud of her. Think of everything she's been through. Being sold into slavery at an early age. Coming over here. Not having a family," Abend said. "The resiliency she has is just amazing. The fortitude. Not falling apart. Not being a destroyed soul."

Abend remembers interviewing Hall, then 13, with the help of an Arabic interpreter for the first time when she was being cared for at the Orangewood Children's Home in Orange. Her captors told her to never speak to police, that officers would beat her. She stayed tight-lipped until she was allowed to call her parents in Egypt, and her father ordered her to go back with her captors.

"That's when I saw a spark," Abend said. "She stood up to her dad. She said, 'No! This is not right. What they did to me was not right. You sold me into slavery.'"

At 13, Hall decided that she wanted to stay in the U.S. She hasn't returned to Egypt or seen her family.

In recent years, Hall has spoken to groups across the country about combating human trafficking. She's briefed ICE agents about the emotional and physical trauma victims face.

In 2010-11, federal immigration officials launched 651 investigations into human trafficking, arresting 300 people. According to the U.S. State Department, there are more than 12 million people entrapped in some form of slavery worldwide.

Hall said her dream now is to become a federal agent for ICE to help crack down on human trafficking and free the enslaved.

"That's my top goal," Hall said. "I've been through it. I know I can help."

Los Angeles immigration attorney Angelo Paparelli, who represented Hall pro bono, said that her citizenship application was filed under a special provision for juvenile immigrants and that county officials from the outset supported her decision to stay in the U.S.

"She has literally gone through a living hell, and now she wants to give back," said Paparelli, of the national law firm Seyfarth Shaw. "She's there to give other people courage."

For now, Hall is living in Beaumont in Riverside County and working at the Cabazon outlets as a store supervisor. She's deciding whether to go back to college to finish a degree or to apply for the local police force.

"I'm very excited. I can start my career now," she said. "I can start my life."

phil.willon@latimes.com