Iranian authorities released a close ally of Mahmoud Ahmadinejad from custody on Wednesday, a day after the president denounced the arrest and pledged to pursue the case, the official IRNA news agency reported.
The report quoted an unnamed official as saying Saeed Mortazavi, a senior official who once served as Tehran's prosecutor general, has been released.
Mortazavi has been at the center of an escalating confrontation between Ahmadinejad and his conservative rivals in parliament ahead of the June presidential election.
His release is seen as a decision to stave off an escalation among the country's senior officials.
There was no immediate indication of any charges against Mortazavi, who now heads the state Social Security Fund.
Mortazavi's lawyer Mohammad Aslani confirmed his client's release but did not elaborate, the semi-official ISNA news agency said.
A parliament probe two years ago found Mortazavi responsible for deaths by torture of at least three anti-government protesters who were jailed during mass protests in the wake of Ahmadinejad's disputed re-election in 2009.
Mortazavi was taken to prison at midnight Monday, and speculations soared that this was related to the prison deaths.
The detention came a day after Ahmadinejad showed parliament a barely audible video showing Fazel Larijani, brother of parliament speaker Ali Larijani, meeting with Mortazavi and allegedly seeking a bribe from the former prosecutor. The bribe allegedly sought was in exchange for getting Ali Larijani to support a business deal involving a company linked to Mortazavi. Ali Larijani denied any links to the video.
Ahmadinejad on Tuesday denounced Mortazavi's arrest, accusing the judiciary of being run as a "family institution" — a reference to the Larijanis, whose brother, Ayatollah Sadeq Larijani, is Iran's judiciary chief — and saying he would pursue the case after his return from an Islamic summit in Cairo.