Iran on Monday executed an Iranian-born opponent of the government who had German citizenship and lived in the United States, the country’s judiciary announced, four years after Iranian agents abducted him in Dubai, according to members of his family.

Iranian authorities had accused the man, Jamshid Sharmahd, 69, of helping orchestrate a deadly terrorist bombing in Iran in 2008, a charge he and his family denied. Mr. Sharmahd was convicted in a trial that human rights groups and Western governments denounced as a sham.

Mr. Sharmahd had permanent U.S. residency and was living in California at the time of his seizure. He operated the website of Kingdom Assembly of Iran, a little-known group also known as Tondar, and made videos claiming that the group was arming people to fight against Iran. The group is committed to overthrowing the government in Tehran and restoring the monarchy, and it has taken responsibility for attacks in Iran.

The family of Mr. Sharmahd, who lived much of his life in Germany and had dual German and Iranian citizenship, has said that Iranian agents abducted him in 2020, when he was visiting Dubai. Iranian law enforcement said at the time that it had captured him in a “complex operation” but did not say where.

Ten years earlier, a man whom prosecutors called an Iranian agent pleaded guilty in Los Angeles to trying to hire someone to kill Mr. Sharmahd, but the reputed agent fled the United States before he could be sentenced.

While Iran has executed many opponents of the government, Mr. Sharmahd’s Western citizenship and residency made his case unusual and drew international attention. Iran has not often put dual citizens to death, but it executed two such dissidents last year: Alireza Akbari, a British Iranian citizen, and Habib Chaab, a Swedish Iranian, who was reported abducted in Turkey and taken to Iran.