(CNN) For years, John Christopher Smith suffered in silence as his manager at a South Carolina restaurant physically abused him and forced him to work over 100 hours a week without pay, federal officials say.
Bobby Paul Edwards, 53, used violence, threats and intimidation on the African-American employee who worked at the eatery in Conway, according to the US Justice Department. It said Edwards hurled racial epithets at him, beat him with a belt, and hit him with pots and pans.
This week, Edwards pleaded guilty to one count of forced labor in the incidents, which allegedly happened when he managed the restaurant between 2009 and 2014.
Authorities said Smith had intellectual disabilities, and was afraid of losing his job. At times, Edwards, who's white, would burn Smith's bare neck with hot tongs to make him work faster, federal authorities said. Other times, he'd allegedly beat him with a belt and punch him with his fists.
"Human trafficking through forced labor can happen on farms, in homes, and as today's case shows -- in public places, such as restaurants," Acting Assistant Attorney General John Gore said Tuesday.
"Edwards abused an African-American man with intellectual disabilities by coercing him to work long hours in a restaurant without pay. Combating human trafficking by forced labor is one of the highest priorities of this Justice Department."
Edwards admitted to using "violence, threats, isolation and intimidation" to force Smith to work despite the ill treatment, officials said.
In an interview last year with CNN affiliate WPDE, Smith said Edwards physically abused him for years and forced him to live in a room behind the restaurant, keeping him away from his relatives. When Smith's family came to the restaurant, the manager would force him to stay in the kitchen, he said.
"I wanted to get out of there a long time ago. But I didn't have nobody I could go to," he told the affiliate. " I couldn't go anywhere. I couldn't see none of my family."
Smith said he started busing tables and washing dishes at the restaurant when he was 12, but the alleged incidents started when Edwards took over as manager.
In October 2014, a frequent customer noticed the scars on his body when he was putting food down and called authorities, who removed Smith from the restaurant, the affiliate said. The victim is about 40 years now.
The NAACP office in Conway pushed for tougher charges after a local court accused Edwards of assault, a misdemeanor, CNN affiliate WMBF reported.
"We are talking about enslavement here," Abdullah Mustafa, president of the local chapter of the NAACP, said at the time. The organization was instrumental in helping file complaints with the Justice and Labor departments.
"This defendant abused a vulnerable victim, and today's guilty plea holds the defendant responsible for his criminal acts," said Sherri Lydon, the United States attorney for the District of South Carolina.
Edwards faces up to 20 years in prison when he's sentenced, a $250,000 maximum fine, and mandatory restitution to the victim. It's unclear when he will be sentenced.