Iran has sentenced Iranian-American art dealer Karan Vafadari and his wife, Afarin Neyssari, to prison, according to a New York-based rights group on Wednesday. They were arrested in July 2016.

The couple, who are Zoroastrians, were allegedly targeted for their faith and their ties to Western nations. The case spotlights an increase by hard-liners in Tehran who have sought to imprison dual nationals under a little-used law. 

Vafadari was sentenced to 27 years in prison, while Neyssari, who has permanent residency in the U.S., received a 16-year sentence, the Center for Human Rights in Iran said.

Zoroastrianism is a pre-Islamic ancient religion whose adherents can face discrimination in Iran. The couple allegedly had parties where alcohol was served to both men and women, which is allowed in their religion. The parties, as well as Vafadari's work as an art dealer, may have raised flags with intelligence forces in Iran's Shiite cleric-dominated government.

"Fortunately, the initial, baseless security accusations that led to our arrest were dropped, but our gallery, office, warehouses and home remained locked and our cars, computers and documents were confiscated, followed by accusations and interrogations that indicated a deeper plot," Vafadari wrote from Tehran's Evin prison.

He added that the sentences mean "my wife and me, and every one of you dual national Zoroastrians who returned to your country to invest in the homeland you love, are always going to be in danger of losing your assets and forced to leave the country."

Correction from AP: The story has been updated to correct the spelling of the wife's last name to Neyssari.