A landmark trial of a former Iranian official linked to the decades-old mass execution of dissidents began in Sweden on Tuesday in a war crimes case that could shed light on the new Iranian president’s own alleged role in the deadly purge. 

Prosecutors in Stockholm have accused Hamid Noury of "intentionally taking the life of a very large number of prisoners sympathetic to or belonging to the People's Mujahedin" in the summer of 1988.

The People's Mujahedin, also known as the Mujahedeen-e-Khalq (MEK), is a now-exiled Iranian resistance group that opposed the Western-backed shah and pushed for the overthrow of the Islamic Republic. The MEK killed several Americans prior to the 1979 Islamic Revolution and was listed as a terrorist organization by the United States until 2012.  

In retaliation for the group’s cooperation with the Iraqi army during the Iran-Iraq War, the Iranian regime forcibly disappeared and executed thousands of dissidents affiliated with the MEK in 1988. Amnesty International estimates more than 5,000 political prisoners were killed across 32 cities under the orders of then-Supreme Leader Ayatollah Ali Khomeini.