The wife of a Princeton University graduate student sentenced to 10 years in prison for espionage in Iran said Tuesday that he is innocent of the charges and urged his release.

“My husband, Xiyue Wang, is one of the kindest, most thoughtful, and most loving men I have ever known,” his wife, Hua Qu, said in a statement. “He has been a devoted husband to me and a father to our four-year-old son.

“Our son has missed his father for more than a year of his young life, as my husband has been unjustly imprisoned for espionage that I know he did not and never would commit.

“My husband has long been deeply interested in 19th and early 20th century Eurasian history, and he was in Iran last summer solely for purposes of learning Farsi and doing scholarly research for his PhD dissertation as a graduate student in history at Princeton University.  We fervently hope that the Iranian authorities will release him soon so that he can return home to his young family.”

Wang was arrested nearly a year ago, but Iran’s judiciary announced his sentencing Sunday. The news was expected to heighten tensions between the United States and Iran, and it shocked the academic world, where international exchange and research is common.

“By all accounts he is a serious and gifted scholar doing historical research,” said Terry Hartle of the American Council on Education. “We hope that Iranian authorities will review his case and release him immediately.

“Hundreds of thousands every year study successfully abroad, including many doing very high-level doctoral research. Sometimes, for very inexplicable political reasons, one of them will run into trouble.” 

Wang is a fourth-year doctoral student at Princeton who was born in Beijing and has earned degrees from the University of Washington and Harvard University. He had become a U.S. citizen and worked for the International Committee of the Red Cross as a translator in Afghanistan and on a business internship with the global law firm Orrick through a fellowship with Princeton in Asia.

He was arrested while researching the Qajar dynasty for his doctorate in late 19th- and early 20th-century Eurasian history, according to Princeton.

Wang was accused of scanning thousands of pages of digital documents and of passing confidential information about Iran to U.S. and British entities, according to the Mizan news agency, which is linked to Iran’s judiciary.

Princeton University’s president, Christopher Eisgruber, told the campus community Monday evening that the university had kept Wang’s arrest confidential as officials worked to secure his release.

“Almost a year ago, Iranian authorities arrested one of our graduate students, Xiyue Wang, and charged him with espionage even though he was in Iran solely for the purpose of doing scholarly research and studying Farsi,” he wrote. “For the past year, the University has been working on a daily basis to try to secure his release and to support him and his family in this exceedingly difficult time.  I am grateful to the people on campus and in our alumni community, and to experts from the private sector and in government, who have assisted our efforts to secure Xiyue Wang’s release from the unjust detention that has threatened his health, pained his family, and distressed all who learned of his plight.

“Until this weekend, the University and his family kept the matter confidential on the recommendation of multiple advisers inside and outside of government who counseled us that publicity might be harmful to our student’s interests.”

He wrote, “We hope the appellate authorities will look mercifully on him when they review his case this summer, and that they will allow this genuine scholar, devoted husband, and caring father to return home to our University and to the wife and young child who miss him dearly.”

Heather Nauert, a spokeswoman for the State Department, said Tuesday that officials from the Swiss Embassy have visited Wang four times.

On social media, there were expressions of shock and concern for Wang.

Erin Cunningham contributed to this report.