Between July and September 1988, the Iranian authorities forcibly disappeared and extrajudicially executed thousands of imprisoned political dissidents in secret and dumped their bodies, mostly in unmarked mass graves. Since then, the authorities have treated the killings as state secrets, tormenting the relatives by refusing to tell them how and why their loved ones were killed and where they are buried. No official has been brought to justice and, in some cases, those involved hold or have held positions of power in Iran. This report calls on the UN to set up an independent investigation to help bring those responsible for these abhorrent crimes to justice.