Iran’s former diplomats have played a critical role in denying and disseminating misinformation about the prison massacres of 1988, as part of a global cover-up of the mass killings orchestrated by the Iranian authorities. This cover-up not only robbed those directly affected and society at large of the right to truth, but also contributed to entrenching impunity, compounding the suffering of survivors and relatives, and facilitating the ongoing commission of the crime against humanity of enforced disappearance and other crimes under international law.