The son of Iran's former president Akbar Hashemi Rafsanjani was released on bail late on Sunday, the office of Tehran's prosecutor said in a statement.
"Following the completion of investigations, Mehdi Hashemi was released after posting the appropriate bail," read the statement published on the Tehran prosecutor website, www.dadsara.ir.
It did not elaborate.
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Hashemi was arrested on arrival in a Tehran airport from abroad on September 23 on charges of undermining national security during the protests that followed the disputed 2009 re-election of President Mahmoud Ahmadinejad.
He had been resident in Britain for the previous three years. Iran had issued an arrest warrant for him in 2010.
Hashemi also faces charges of seeking to disrupt the economy and of corruption linked to oil contracts signed during his father's presidency between 1989 and 1997.
His father is seen as a moderate voice who has been increasingly isolated by hardliners in recent years.
Rafsanjani's daughter, Faezeh Hashemi, is also in prison serving a six-month jail term for "propaganda against the regime."