The man who sent an Iranian-Canadian photojournalist to the prison where she was raped, beaten and murdered was released from custody just a day after being arrested.
Iran's former prosecutor general, Saeed Mortazavi, was arrested Monday and released Wednesday, according to the country's state news agency.
The agency did not say he was taken into custody or why he was let go, but noted the investigation is ongoing.
A 2009 parliament investigation found Mortazavi responsible for the torture and deaths of three anti-government protesters.
Mortazavi also sent Iranian-Canadian Zahra Kazemi to jail for photographing detainees' wives outside Tehran's Evin prison. She was later beaten, raped and killed.
In a lawsuit before Canadian courts, Kazemi's estate is suing the Iranian government, listing Mortazavi as one of the people responsible for her death.
Mortazavi was detained a day after his political ally, President Mahmoud Ahmadinejad, publicly accused the family of Parliament Speaker Ali Larijani of attempting to use their prominence for financial gain.
Larijani is a possible candidate to succeed Ahmadinejad, who is nearing the end of his second term and cannot run again immediately.
The timing of the detention suggested it was linked to the accusations and was a clear indication Ahmadinejad has lost the favour he once enjoyed from Iran's most powerful authority, Supreme Leader Ayatollah Ali Khamenei.
On Wednesday afternoon, Mortazavi resumed work as head of the social security office, Fars news agency reported.
His appointment to the post last year outraged MPs because of his alleged links to the prison deaths.
-- With files from Reuters