Iran had requested the extradition of the Sydney cafe gunman 14 years ago, but was reportedly turned away by Australia.
According to the BBC, the head of Iran's police, Gen Ismail Ahmadi Moghaddam, told reporters that hostage-taker Man Haron Monis was wanted for fraud at the time.
Moghaddam said that in 1996, Monis, who was then working as a manager of a travel agency, fled to Malaysia after committing fraud.
He then traveled to Australia under a fake name.
Moghaddam said that since Iran did not have an agreement on the extradition of criminals with Australia, the Australian police refused to extradite him.