BOSTON — The owner of a Boston pizza parlor is accused of physically and verbally abusing a longtime immigrant employee who could not legally work in the U.S., forcing the employee to work long hours, and threatening to turn him over to immigration authorities if he protested, federal prosecutors said Thursday.

Stavros Papantoniadis, 47, who also goes by Steve, was charged with forced labor according to a statement from the U.S. attorney’s office in Boston. He is being held pending a detention hearing scheduled for Monday.

An email seeking comment was left with his federal public defender.

Papantoniadis, who lives in Westwood, owns and operates two Stash’s Pizza locations in Boston and formerly owned several other pizza parlors in suburban communities, prosecutors said. No one was available to discuss the case at the restaurant’s two locations.

U.S. Attorney Rachael Rollins called forced labor a form of human trafficking.

“The allegations in this case are horrific,” she said. “Nobody has the right to violently kick, slap, punch or choke anyone, and certainly not an employer to an employee.”

Although he only faces one charge, he victimized at least seven employees, according to court documents.

He deliberately recruited workers who were not in the U.S. legally and therefore not authorized to work, and paid them cash, authorities said.

One employee, a native of a North African country, allegedly worked as much as 119 hours a week at Stash’s Pizza from 2001 to 2015, endured derogatory comments about his religion, and was violently attacked by his employer. The worker was once kicked so hard in the genitals by Papantoniadis that he required surgery, prosecutors said. On another occasion, Papantoniadis hit the worker in the mouth and broke some teeth, prosecutors said.

The worker was so scared that he kept working at Stash’s Pizza, prosecutors said.

Another employee from El Salvador who was not a legal resident of the U.S. told investigators that he worked 80 hours per week, seven days a week and was not paid overtime. He reported having food thrown at him and being denied time off to see a doctor for serious medical issues.

The worker, who is gay, said Papantoniadis also made derogatory comments about his sexual orientation.

This is not the first time Papantoniadis has been in federal court. In 2017 he was accused of violating federal minimum wage, overtime, and child labor laws, according to federal court records. In that case he agreed to pay $330,000 in back wages and overtime.

The investigation is ongoing and federal investigators asked anyone who thinks they may have been a victim to contact them.