Monis was killed after Australian security personnel stormed the ritzy chocolate shop where he had kept numerous people hostage. Two others are dead, according to Sydney police.

The gunman made hostages hold up black flags with Arabic writing along the shop's facade, similar to the banners of Salafist militant groups elsewhere. He "sought to cloak his actions in the symbolism of the [Islamic State] death cult," said conservative Australian Prime Minister Tony Abbott.

But judging from his troubled past and criminal record, it's more than possible Monis was a fringe, disturbed individual carrying out an act with no genuine connection to any organization or cause.

"This is a one-off random individual," a lawyer who had once represented Monis told Australian media. "It's not a concerted terrorism event or act."

The incident, though, raised immediate concerns over religious tensions and Islamophobia in Australia. The solidarity hashtag #Illridewithyou that trended on Twitter did not just come out of the ether. It drew upon the fears of many worried about anti-Muslim, anti-immigrant sentiment in the country, which like many other Western nations, is in the midst of its own debate over multiculturalism.

The issue of asylum, in particular, takes up great space in the Australian conversation. The conservative Abbott won elections in September 2013 in part on a campaign to "Stop the Boats," a reference to the thousands of migrants attempting to reach Australia illegally by sea. New hard-line policies instituted by Abbott's government to push back boats crammed with would-be refugees have thinned numbers of asylum seekers arriving in Australia from some 20,000 last year to just over 150 this year. A survey by the Lowy Institute, an Australian think tank, found that 71 percent of the country approved of the Abbott government’s tougher stance.

But the measures have earned considerable criticism within Australia and abroad. The Australian government directs the asylum seekers it intercepts -- many of whom come from war-ravaged or conflict-ridden countries in the Middle East and South Asia -- to offshore facilities away from the Australian mainland. These include Papua New Guinea, the tiny island-state of Nauru and the Australian territory of Christmas Island.

Critics have labeled these detention centers Australia's "Pacific Gulag," with rights group citing reports of abuse and mistreatment. Earlier this year, ten Pakistani asylum seekers kept in a facility on Manus Island, off Papua New Guinea's coast, even wrote letters to President Obama begging for him to intervene. "You are the only hope for us to give us a new life," they wrote, in a letter published by the Guardian. "We beg for your help to take us out of this miserable situation." Two Iranian men had died in the camp -- one beaten to death by local guards, the other from an infection brought on by a cut on his foot.

"The Manus Island detention centre is unfit for human habitation," asylum advocate Liz Thompson tells the Financial Times.

In November, Australia turned a boat filled with Sri Lankan asylum seekers over to Sri Lankan authorities, who proceeded to charge the would-be refugees for illegally attempting to leave the country. Many were ethnic Tamils claiming persecution at the hands of Sri Lanka's Sinhalese Buddhist majority government.

Last week, Human Rights Watch issued a statement condemning these actions: "Australia’s actions in the Indian Ocean show the yawning gap between its practices and international legal principles," said Elaine Pearson, the group's Australia director. "Australia shouldn’t ignore the well-documented and politically motivated torture, rape, and ill-treatment of many men and women detained by Sri Lankan security forces."

This summer, the Australian government kept one boat full of Tamil asylum seekers at sea for almost a month as it wrangled over their fate with other governments. The migrants were eventually relocated to a facility in Nauru. One Sri Lankan asylum seeker offered this testimony:

There were women and children on the boat. There was even a pregnant woman. There were people who were sick and people who had heart problems. We all suffered a lot. I was locked in a room with 80 people. I was kept apart from my wife and children and was very worried about them.

The Australian government has issued temporary visas to thousands of asylum-seekers and is processing more. Last week, though, Abbott's government pushed through new, tougher legislation that would block asylum seekers from any right to permanent visas and, in some instances, mandate their deportation back to home countries should it be deemed safe. Critics say aspects of the new legislation contravene international conventions on the rights of refugees.

The Economist examines what may be motivating the Abbott government here:

According to the Refugee Council of Australia the numbers heading for Australia are often overblown: Yemen received more than roughly 25 times more boat people than did Australia over the past six years. But as Mr Abbott’s government has languished in opinion polls for much of 2014, failing to steer some key provisions from its first budget through the Senate, it is hoping this get-tough policy on asylum-seekers will score it political points.

The harshness of Australia's policies curbing asylum seekers contrasts both with Europe's predicament -- which copes with a far greater influx in the Mediterranean -- and Australia's own open immigration policies. Twenty-seven percent of the Australian population is foreign born; this is hardly a closed society.

 But anti-immigration voices are now piping up in the aftermath of the Sydney attacks. "Some Australians recognize that this likely terrorist attack is a result of the poor immigration decisions of Australian governments, both conservative and liberal, over the last four decades," writes conservative commentator Nick Adams.

It remains to be seen how far a shadow the tragic events in Sydney may cast over a larger national conversation.

The Washington Times