The owner of a pizza chain who was found guilty earlier this year for blackmailing undocumented employees into working long hours at his restaurants, sometimes without pay, has been sentenced to more than eight years in federal prison, the U.S. Attorney’s Office for the District of Massachusetts announced Monday.

Stavros “Steve” Papantoniadis, 49, the owner of Stash’s Pizza, was sentenced to eight and a half years behind bars and will be required to pay a $35,000 fine following his release, according to the announcement. Federal officials in Massachusetts said Papantoniadis hired undocumented people in order to exploit them…

Prosecutors said Papantoniadis physically abused and threatened five men and one woman, who he purposely hired because they lacked immigration status. He would constantly demean and insult his employees, who were working 14 or more hours per day and as many as seven days per week, and would withhold their wages.

One worker, a Muslim man from a North African country…said Papantoniadis would make derogatory comments about his religion and was otherwise abusive…

Prosecutors said that on several occasions, Papantoniadis would assert his control when he learned of an employee’s desire to quit, threatening workers with physical harm or deportation…