Loved ones held a vigil Thursday night for a Princeton University student who has been imprisoned in Iran for more than three years.

Hua Qu says that her husband Xiyue Wang does not belong in prison. She and others are calling for his immediate release.

Wang went to Tehran, Iran to conduct research for his doctoral thesis. He was arrested in 2016 and was charged and convicted of espionage. He was sentenced to 10 years in prison by Iranian authorities.

Qu says that the last time she saw her husband was at Newark Liberty International Airport as he left for Iran. Their son was 3 years old at the time – he is now 6 and a half. Que says that she hopes her husband will be able to see their son grow up.

"It is really unacceptable for him to have been kept away from us for such a long time,” she says. "I mean three years precious time in our lives and in our young son's life has been stolen."

Qu says that her husband’s sentence was unjust and that he is innocent.

"We really hope to have the mercy and the clemency from the Iranian government and I hope our government - the United States government - can do more for this innocent man who was criminalized only because of the navy-blue passport he holds,” says Qu.

Qu spoke with Wang before the vigil by telephone, so he knew that it was happening. It was held at the Chancellor Green Rotunda on the Princeton campus. Several speakers shared remarks and read a message from Wang himself.

"Gradually I have learned to adapt and compartmentalize things. To keep the unpleasant at bay, I focus on songs like ‘The Internationale,’” Wang wrote.

Wang could be imprisoned until 2026.

Qu says she hopes the Iranian government can speak with other members of the international community, including the United States government, to have her husband released on humanitarian grounds.