A senior member of a U.S.-based Iranian opposition group accused of orchestrating a deadly 2008 mosque bombing has been sentenced to death in Iran, authorities said Tuesday.

Iranian authorities say Jamshid Sharmahd, an Iranian-German national and U.S. resident, is the leader of the armed wing of a group advocating the restoration of the monarchy that was overthrown in the 1979 Islamic Revolution.

His family has said he was merely the spokesman for the opposition group and accuses Iranian intelligence of abducting him from Dubai in 2020. His hometown is Glendora, California.

The death sentence, which can be appealed, comes against the backdrop of months of anti-government protests in Iran and a fierce crackdown on dissent. Monarchists based outside Iran support the protests, as do other groups and individuals with different ideologies.

The official website of Iran’s judiciary said he was convicted of plotting terrorist activities. He was tried in a Revolutionary Court, where proceedings are held behind closed doors and where rights groups say defendants are denied due process.

Iranian authorities have accused him of planning a series of attacks, including the mosque bombing, in which 14 people were killed and more than 200 were wounded. He has also been accused of working with U.S. intelligence and spying on Iran’s ballistic missile program.