Hamid Noury, 61, who was arrested at a Stockholm airport in 2019, was charged with war crimes for the mass execution and torture of political prisoners at the Gohardasht prison in Karaj, Iran, in 1988.

“The accused has in the role of assistant to the deputy prosecutor at the Gohardasht prison in Karaj, Tehran jointly and in collusion with others been involved in the executions, which took place after a fatwa from Iran’s supreme leader,” Stockholm District Court said in a statement.

It said those were deemed as a “serious crime against international law” and murder. “The sentence is life imprisonment,” the court said.

Amnesty International has put the number executed on government orders at around 5,000, saying in a 2018 report that “the real number could be higher”. Iran has never acknowledged the killings.

Noury, who denies the charges, is the only person so far to face trial over the purge that targeted members of the Iranian People’s Mujahideen, which was fighting in parts of Iran, as well as other political dissidents.

His lawyer was not immediately available for a comment.

Iranian Foreign Ministry did not immediately respond to a Reuters request for comment after the verdict, but yesterday its spokesman told a news conference Sweden should release Noury “as soon as possible”.

The trial has focused unwelcome attention on Iran’s hardline president Ebrahim Raisi, who is under US sanctions over his past actions that include what Washington and activists say was his involvement as one of four judges who oversaw the 1988 killings.

Raisi, when asked about the allegations, told reporters after his election in 2021 that he had defended national security and human rights.

The case has soured relations between the two countries with Iran calling the trial “illegal”.

Under Swedish law, courts can try Swedish citizens and other nationals for crimes against international law committed abroad.