A Massachusetts student who was held by the Iranian government for 40 days before being released this weekend is back in America. 

The Boston Globe reported that Matthew Trevithick was greeted by his mother at Boston's Logan International Airport Sunday evening. According to the paper, Trevithick left Iran on a civilian flight Saturday before returning to Boston from Istanbul. 

Trevithick, 30, was released on the same day that four other Americans -- former Marine Amir Hekmati, pastor Saeed Abedini, Washington Post reporter Jason Rezaian and Nosratollah Khosravi-Roodsari -- were freed by Tehran in a separately negotiated prisoner exchange.

Trevithick, of Hingham, Mass., had traveled to Iran in September for a Farsi language program at an institute associated with Tehran University. It is unknown why he was held in Evin Prison for more than a month.

We actually know very little about that," a State Department official told the Globe when asked about Trevithick's detention and treatment by Iran during his captivity. "There was never any public announcement by the Iranians of his detention and never any public announcement about the charges."

The official told the Globe that U.S. Secretary of State John Kerry, a former senator from Massachusetts, had personally pressed the Iranians to release Trevithick. 

Trevithick is the co-founder of SREO, a humanitarian crisis research center based in Turkey. The Globe reported that he was previously worked at the American University of Iraq and the American University of Afghanistan.

He loves the Middle East. He loves understanding the nuance of what goes on there,” his father, Paul, told the Globe. “He has been traveling the Middle East for years. He has been involved in a dangerous part of the world, so he’s not naive about the risks."

The Associated Press contributed to this report.

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