The infamous Iranian official blamed for the 2009 prison death of the Canadian photojournalist Zahra Kazemi is in jail now, but Ms. Kazemi's son cautions that the arrest of the former Tehran prosecutor may just be a superficial development.
"Mortazavi is nothing. He's a small fish," Stephan Kazemi said in an interview Tuesday.
Once known as "the Butcher of the Press" for his repression of Iranian media, the former prosecutor, Saeed Mortazavi, was arrested Monday night, according to Iranian news agencies.
The reason for his detention wasn't immediately provided. But Mr. Mortazavi might have been a casualty of an ongoing dispute between two factions among Iran's conservative leaders.
The feud has pitted Mr. Mortazavi's mentor, the populist President Mahmoud Ahmadinejad, against the powerful Larijani family, who are closely aligned with the Muslim clergy. The five Larijani brothers include Sadegh, who is the head of the judiciary, and Ali, the speaker of the Iranian parliament.
Mr. Mortazavi is considered the main suspect in the death of Ms. Kazemi, an Iranian-Canadian photographer who was arrested in 2003 after taking pictures outside Tehran's Evin prison.
An inquiry ordered by then-president Mohammed Khatami concluded that Ms. Kazemi died from a beating. Mr. Mortazavi was alleged to have been present during the interrogation.
Mr. Mortazavi, described by Human Rights Watch as a "serial human rights abuser," was dismissed from his judicial post following a 2010 inquiry by the Iranian parliament that held him responsible for the torture deaths in custody of three protesters whom he ordered to jail after the disputed 2009 presidential elections.
Mr. Mortazavi was then named to head the country's social security fund, the Social Welfare Organization, but Iranian lawmakers and Mr. Ahmadinejad clashed over that appointment.
Ms. Kazemi's son has waged a long judicial battle against Iran after his mother's death. But he said he found little solace from Mr. Mortazavi's arrest, saying the ex-prosecutor is just a pawn being sacrificed by more powerful players in Iran's theocracy.
"Every time the regime is in danger, they make sacrifices among themselves," Mr. Kazemi said.
He said he doesn't seek vengeance against Mr. Mortazavi but broader reforms in Iran. "They could torture this guy to death. It wouldn't be justice," he said.
Mr. Kazemi used to be known by the family name Hashemi. A Montreal resident, he has sought damages from the Islamic Republic of Iran and Mr. Mortazavi in Quebec civil courts. However, lawyers for both the Iranian and Canadian governments argued that the Kazemi estate can't sue because of Canada's State Immunity Act.
Mr. Kazemi is now seeking leave to appeal before the Supreme Court of Canada.
Reasons for Mr. Mortazavi's arrest remain murky, but his name was raised in a bitter debate in the Iranian parliament on Sunday.
Mr. Ahmadinejad, in trying to stave off the impeachment of one of his ministers, said he had a video of a conversation where another Larijani brother, Fazel, tried to engage Mr. Mortazavi in an illegal business deal, according to Iranian news agencies.
A day later, Mr. Mortazavi was arrested.
Reports by the official Fars news agency gave conflicting reasons for his arrest. One article said Mr. Mortazavi was possibly detained for his role in three 2009 prisoners' deaths. Another Fars dispatch said he was held on charges of "illegal possession of government properties."
"We don't know what the story is. There's no real logic to how this regime works," Mr. Kazemi said.