BOSTON (NEXSTAR/WWLP) — The owner of a Boston-area pizzeria chain was convicted on charges of forced labor after authorities said he threatened his workers with physical harm and deportation in order to keep some of them working 14-plus hours per day for as many as seven days per week.

Stavros Papantoniadis, the owner of Stash’s Pizza, was arrested March 16, 2023, NewsNation affiliate WWLP previously reported. At the time, he was charged with a single count of forced labor, following allegations that he had intentionally hired workers without immigration status so he could subject them to unfair working conditions.

Authorities alleged that Papantoniadis, 48, threatened employees with deportation and used violence to scare the victims over the span of 14 years.

“To maintain control of those undocumented workers, he made them believe that he would physically harm them or have them deported. He monitored the workers with surveillance cameras, which he accessed from his cell phone, and constantly demeaned, insulted and harassed them,” reads a news release issued Friday by U.S. Attorney Joshua S. Levy of the District of Massachusetts.

Levy said Papantoniadis had forced or “attempted to force” six victims (five men, one woman) to work at his pizzerias. Some of the allegations against Papantoniadis included: choking one of the workers when the employee announced intentions to quit; telling another he would kill him; and chasing a fleeing worker down a highway, after which he “falsely reported the victim to local police” to coerce the worker into staying.

Papantoniadis was ultimately indicted on charges of forced labor and attempted forced labor, and later two counts of wire fraud, WWLP reported. He was convicted Friday of three counts each of forced labor and attempted forced labor. Each carries a possible prison sentence of 20 years, five years of supervised release and up to $250,000 in fines as well as additional restitution.

“Forced labor is a serious violation of human rights, and no one in the United States should live in fear of abuse and coercion in their workplace,” Levy said. “I commend the tireless efforts of our law enforcement partners who worked collaboratively to bring this defendant to justice.”

Papantoniadis’ sentencing is scheduled for Sept. 12.

Papantoniadis owns and operates Stash’s Pizza, a chain with locations in Dorchester and Roslindale, and had operated previous pizzeria locations in Norwood, Norwell, Randolph, Weymouth, and Wareham, Massachusetts