SYDNEY, Australia - Before he was killed in a Sydney cafe, the gunman who held hostages there for more than 16 hours was no stranger to police.
The hostage-taker was Man Haron Monis, an official with direct knowledge of the situation said Monday.
"He had a long history of violent crime, infatuation with extremism and mental instability," Australian Prime Minister Tony Abbott told reporters.
Australian media reports paint a harrowing picture of Monis and his lengthy criminal history.
The self-styled Muslim cleric, also known as Sheikh Haron, pleaded guilty last year to writing offensive letters to the families of Australian troops.
That same year, he was charged with being an accessory to the murder of his ex-wife, the Australian news reports said.
In April, sex crimes detectives arrested Monis and charged him with sexually assaulting a woman in western Sydney in 2002, according to The Sydney Morning Herald. Other sex-related charges were added regarding six additional victims, the newspaper said. Police reportedly said Monis was using the name Mohammad Hassan Manteghi and claimed to be a "healer."
Monis was out on bail, the reports said. He was sentenced to 300 hours of community service after sending letters to the families of Australian soldiers who died in Afghanistan. The letters were "sadistic, wantonly cruel and deeply wounding," one High Court judge said at the time, according to CNN affiliate Seven News.
Monis was an Iranian refugee living in Australia who used the Internet to spread extremist beliefs.
"He posted graphic extremist material online," Abbott said.
And during the siege, Abbott said, the hostage-taker "sought to cloak his actions with the symbolism of the (ISIS) death cult," Abbott said.
In social media posts, Monis appears to embrace a radical Sunni extremist theology.
On his apparent website, there's a pledge of allegiance to the so-called Islamic State terror group.
The site describes Monis as a Muslim cleric and activist based in Sydney who has "continuously been under attack & false accusation by the Australian government & media since he started his political letter campaign from 2007."
There's a graphic photo of slain children at the top of the site. Under the image, it reads, "This is an evidence for the terrorism of America and its allies including Australia. The result of their airstrikes."
A description on the site portrays Monis as a victim of a political vendetta and compares him to Julian Assange, the WikiLeaks founder who has claimed the sex crime allegations he faces are politically motivated.
A YouTube video posted in November shows Monis standing on a street corner, chains draped over him, carrying a sign that says, "I have been tortured in prison for my political letters."
His former lawyer, Manny Conditsis, told Australian public broadcaster ABC that Monis was an isolated figure who was probably acting alone.
"His ideology is just so strong and so powerful that it clouds his vision for common sense and objectiveness," Conditsis said.
The ABC report said Monis had been granted political asylum in Australia.
Monday's hostage situation began around 10 a.m. Hundreds of police officers, including snipers, took position around the Lindt Chocolate Cafe in Sydney's central business district.
Australian media captured haunting images of hostages pressing their hands against the cafe's windows. They were reportedly taking turns holding a black flag with Arabic writing on it that said, "There is no God but God and Mohammed is the prophet of God."
The man holding the hostages demanded to speak to Abbott. Police were monitoring social media because hostages appeared to be posting information about the man's demands.
Hours into the crisis, at least five hostages managed to escape, running terrified toward police in riot gear. That made the hostage-taker furious, reported Chris Reason, a correspondent for CNN affiliate Seven Network. Reason said he could see the gunman become "extremely agitated" when he realized what had happened, and he "started screaming orders" at the remaining hostages.
Gunfire erupted early Tuesday as police stormed the cafe where the gunman had been holding hostages.
Two hostages were killed during the standoff. Police later announced that the siege was over and that the lone gunman had been killed.