The man responsible for a deadly siege in a Sydney cafe was given a gun licence despite his long criminal history, Australia's Prime Minister has revealed.
Tony Abbott has ordered an urgent inquiry into why Iranian-born Man Haron Monis was not under surveillance and how he obtained Australian citizenship.
Mr Abbott said Monis was on the national security agency's watch list in 2008 and 2009, but was later dropped off it for reasons unknown.
Armed with a shotgun, Monis took 17 people hostage at the Lindt Chocolat Cafe in central Sydney during the morning rush hour on Monday.
Two hostages - 34-year-old Tori Johnson and 38-year-old Katrina Dawson - were killed along with Monis 16 hours later after police stormed the cafe to free the captives. It is not yet clear who fired the shots that killed the hostages.
The 50-year-old self-styled cleric - whom Mr Abbott called "a madman" - had a long history of criminal offences and was out on bail at the time of the siege.
He had been charged with being an accessory to the murder of his ex-wife and dozens of sexual assault offences.
Mr Abbott said Monis had been placed on the Australian Security Intelligence Organisation's watch after sending a series of offensive letters to the families of soldiers killed in Afghanistan.
He was convicted and sentenced last year to 300 hours of community service for sending what a judge called "grossly offensive" letters.
Just three days before the siege, Australia's highest court refused to hear his appeal against the conviction.
"Plainly there are questions to be asked when someone with such a history of infatuation with extremism, violent crime and mental instability should be in possession of a gun licence," Mr Abbott told reporters.
"We have very tough gun laws and I guess we can be pleased that he didn't have a more potent weapon at his disposal. But why did he have a gun licence in the first place?
"We particularly need to know how someone with such a long record of violence and such a long record of mental instability was out on bail after his involvement in a particularly horrific crime," Mr Abbott said.
"And we do need to know how he seemed to have fallen off our security agency's watch list back in about 2009.
"I don't know why he dropped off the watch list in those days, I really don't," the Prime Minister said.
Mr Abbott said the review, which is due to report back in late January, would examine Monis' arrival in Australia from Iran in 1996, the decision to grant him asylum and citizenship and what welfare he received.
The investigation would also look at how he accessed a gun as well as the information agencies had about him and how it was shared.
Meanwhile, thousands of Australians continue to pay tribute to the victims at a memorial at the cafe in Sydney's Martin Place.
Small boxes of Lindt chocolates have been left among the mountain of flowers and cards in honour of Mr Johnson, who was the cafe's manager, and Ms Dawson, a lawyer and mother of three.
