An Iranian reformist Web site reported Wednesday that authorities have arrested an opposition official who was investigating the abuse of protesters in post-election unrest.
The site (www.mowjcamp.com) said Alireza Beheshti was arrested Tuesday.
Beheshti is a senior aide to opposition leader Mir Hossein Mousavi, and heads a commission looking into post-election abuse. He recently said more than 70 people died during the unrest that followed the disputed re-election of President Mahmoud Ahmadinejad.
On Tuesday, Iranian authorities closed the offices of defeated presidential candidate Mehdi Karroubi, a leading critic of Iran's post-election crackdown.
A spokesman for Karroubi's political party, Esmaeil Gerami Moghaddam, says security agents with a prosecutor's warrant sealed off the premises and told Karroubi and others to leave.
Moghaddam said agents confiscated documents, records and computers.
The opposition leader's claims of detainee abuse have angered Iran's hardliners. The Iranian parliament speaker has rejected Karroubi's claims as "baseless."
Authorities put a temporary ban on Karroubi's newspaper after it printed the rape allegations.
President Ahmadinejad was re-elected in the controversial June vote that saw Mr. Mousavi finish second. Government opponents say the election was fraudulent, and it set off days of street demonstrations.
Thousands of Iranians were arrested during the post-election protests.
Some information for this report was provided by AFP and Reuters.