The trial of former Tehran prosecutor Said Mortazavi has begun behind closed doors.
Mortazavi, an ally of President Mahmud Ahmadinejad, is charged with misleading the investigation into the deaths of protesters arrested in the 2009 postelection crackdown.
Mortazavi and two judges will reportedly be tried for their roles in the transfer of opposition detainees to the Kahrizak detention center, where at least three were tortured to death.
Mortazavi spent one night in jail earlier this month on unknown charges.
His arrest is believed to have been tied to an ongoing power struggle between Ahmadinejad and his powerful opponents in the regime.
Mortazavi, who currently heads Iran’s social-security organization, has been nicknamed the "Butcher of the Press" over his role in closing reformist publications and jailing journalists.
He has been also tied to the 2003 death of Iranian-Canadian photojournalist Zahra Kazemi.
With reporting by ILLN and ISNA