The owner of a Boston pizza chain was arrested Thursday for allegedly forcing an employee who was an undocumented immigrant to work for him for years while threatening him with deportation and subjecting him to repeated verbal and physical abuse. Prosecutors allege that he physically abused and threatened employees for approximately 14 years, targeting victims who lacked immigration status, employing them at depressed wages and demanding that they work six or seven days a week, at times for longer than eight hours a day and often without breaks or overtime compensation. He also allegedly withheld wages in some cases.