This report documents and analyzes the Iranian government’s massacre of political prisoners in 1988. Pursuant to a fatwa issued by then-Supreme Leader Ayatollah Khomeini, the government systematically interrogated, tortured and summarily executed thousands of political prisoners. Many families were never informed about the executions and many of the victims were buried in unmarked mass graves. The Iranian government has never identified those who were secretly executed and tortured, and has never issued an explanation for this crime.