Aftab Ali Khan, 28, was accompanied by Immigration and Customs Enforcement officers on a flight from Logan International Airport to Islamabad, the agency said in a statement. Khan, his uncle and a man in Maine were arrested on immigration violations nearly two weeks after the failed bombing attempt on May 1, 2010.
Khan pleaded guilty last month to immigration and illegal money-transfer charges and was sentenced to time served. He did not face terrorism-related charges.
Khan, who lived in Watertown, came to the U.S. in August 2009 on a 90-day visa to get married.
Prosecutors alleged that Khan gave $4,900 to Faisal Shahzad, of Bridgeport, Conn., who was later convicted in the bombing attempt.
They said it was part of a transaction to get an equivalent amount of money to Khan's family in Pakistan.
Khan is not accused of knowing what Shahzad would do with the money. But investigators say they uncovered fraudulent immigration documents and that Khan lied to them while they were investigating the Shahzad case.
Shahzad, who admitted leaving an SUV rigged with a homemade bomb in busy Times Squares, was arrested trying to leave the country on a Dubai-bound flight two days later. He was sentenced to life in prison.