A 30-year-old dual Iranian-American citizen and former U.S. Marine has had his death sentence commuted to a 10-year prison term by an Iranian appeals court, the Associated Press reported on Saturday.

Amir Mirza Hekmati, who was born in Flagstaff, Ariz., and later moved with his family to Flint, Mich., was charged with spying for the CIA while in Iran and has been held largely in secret at one of Iran’s most notorious prisons for the past three years.

In a statement on a Facebook page called Free Amir Hekmati, his family greeted news of Hekmati's conviction with a "heavy heart."

"The Hekmati family respectfully asks senior Iranian officials to review Amir's conviction, and to resolve this grave misunderstanding by granting Amir his freedom and a safe return home," the man's family said in the Facebook statement.

Congressman Dan Kildee, D-Flint, who has represented the Hekmati family in Congress and advocated for the man's release, called the charges against him "categorically false," in a statement released on Saturday following reports of Hekmati's secret retrial in Iran. 

Hekmati’s fluency in Farsi and interest in languages was highly valued while he served in the Marines. While serving he learned Arabic and was deployed in Iraq in 2003 and 2004. After his service, he used his translation skills to assist with a Defense Advanced Research Projects Agency-financed study and projects that aroused suspicion in Iranian officials during his first visit to the country in 2011.

He was kidnapped two weeks into that trip on his way to a feast with family members and has been held ever since. He confessed later in 2011 on Iranian state television, and in January 2012, he was sentenced to death in a secret trial. That sentence was brought to a retrial in a matter of months. Some say it was because a death sentence would limit the Iranians’ ability to use Hekmati as a bargaining chip.

The overturned death sentence is a huge victory for the family, who hired influential Persian lawyer Mahmoud Alizadeh Tabatabaei to fight for Hekmati’s release. Tabatabaei hopes he can get Hekmati released after serving three years, which would end up being this August. The lawyer has represented a former Iranian president and a prominent opposition leader currently under house arrest.

“Maybe I can get him released even before that, but a lot depends on the Americans,” Tabatabaei told AP. “If they show their good will, it will become much easier to get Mr. Hekmati freed.”

Tabatabaei has alluded to the possibility of prisoner exchanges for Hekmati, which wouldn’t be out of the ordinary for the U.S. and Iran. The two nations have used prisoner releases to further political deals in the past, most recently in November 2013, when the U.S. released Mojtaba Atarodi, a prominent Iranian scientist who was arrested for trying to buy equipment to further Iran’s nuclear program.

Iran has also participated in prisoner releases. Not long before Atarodi was freed, Iran let 11 prisoners go ahead of Iranian President Hassan Rouhani’s visit to the United Nations.

Hekmati’s trial and captivity have been shrouded in secrecy since he was first snatched in 2011. His family members never received any information about his retrial and even Tabatabaei has had trouble getting any information about the notoriously secretive Iranian court's procedures. The U.S. State Department too has little information on the retrial and declined to confirm the new sentence.

Hekmati is caught between the hard-liners who run the courts and their supports, and the Foreign Ministry and its supporters who are deep in talks with the U.S. over Iran’s nuclear program, according to a New York Times' article. The hard-liners want Hekmati jailed in a show of defiance and power to the U.S., while the more lenient moderates want him freed to send just the opposite message to the U.S.