Nizar Zakka, a US permanent resident from Lebanon who has done work for the US government, was on Monday indicted on unknown charges in Iran along with three dual nationals.

The four were held by Iran’s authorities amid a series of detentions that followed last year’s nuclear deal with world powers.

They all are believed to have been detained by hard-liners in Iran’s paramilitary Revolutionary Guard. The reasons for their arrests remain unclear, though the husband of one of them says his family was told by the Guard she’d be released if the British government agreed to their demands.

Iran’s semi-official ISNA and Tasnim news agencies quoted Tehran’s prosecutor, Abbas Jafari Dowlatabadi, naming the three dual nationals indicted along with the IT expert Zakka as:

– Homa Hoodfar , an Iranian-Canadian woman who is a retired professor at Montreal’s Concordia University;

– Siamak Namazi , an Iranian-American businessman who has advocated for closer ties between the two countries and whose father is also held in Tehran;

– Nazanin Zaghari-Ratcliffe , an Iranian-British woman who works for the Thomson Reuters Foundation, the charitable arm of the news agency.

The four were arrested in connection with separate cases over the past year. Family members and representatives of the four say they did nothing wrong.

Dowlatabadi’s statement did not elaborate on the charges. He said another seven people faced charges related to the unrest that surrounded the country’s disputed 2009 presidential election.