Then he flew to Germany to take his oral exams for his master's degree -- and was arrested and deported to the U.S. He then pleaded guilty to one count each of conspiracy, money laundering and violating the 1995 Iran trade embargo.
He's now serving more than three years in federal prison.
U.S. officials have said his arrest was a blow to Iran's nuclear smuggling networks.
Sairafi tells The Associated Press that he was kidnapped and is a victim of "political disputes" between the two countries.