A deadly hostage situation in Sydney ended after midnight Tuesday with two hostages and the gunman, Man Haron Monis, dead after 16 tense hours and a shootout between Monis and heavily armed Australian police. The standoff lasted from 9:45 a.m. on Monday until 2:15 a.m. Tuesday, Sydney time.

Local media reported that there were 17 people taken hostage Monday morning in the Lindt Chocolate Café in Martin Square, an upscale retail area of Sydney a few blocks from the New South Wales parliament and the Reserve Bank of Australia. Initial speculation was that the hostage-taking was part of a robbery, but after hostages were seen being forced to hold up a “Black Standard” banner proclaiming the Islamic faith, suspicions grew that the attack was religiously motivated.

Monis later requested the official Black Standard of the Islamic State group, which seeks to establish an Islamic caliphate in Syria and Iraq, and wanted to speak with Prime Minister Tony Abbott on the phone. Sydney siege An escaped hostage runs toward a police officer outside the Lindt Café, where other hostages were being held, in Martin Place in central Sydney, Monday, Dec. 15, 2014. Photo: Reuters/Jason Reed

Later in the day, between 4 and 5 p.m., five people were able to flee to safety out of the café’s fire exit. Police brought in bomb robots after Monis claimed he had planted bombs around the building and tried to negotiate with him until the shootout just after 2 in the morning on Tuesday. No bombs were found.

A handful of hostages fled the café just minutes before the shootout. Police reportedly did not plan to move in yet, but did so after gunshots were heard coming from inside. They used flash grenades, which stun victims with a loud auditory bang and a flash of intense light, to incapacitate Monis before moving in.

The New South Wales Police Force said in a statement they are investigating the operation and did not indicate if they knew whether the two hostages were killed by bullets fired by police or by Monis. The two hostages killed, unidentified as of 4 p.m. EST, were a 34-year-old man and a 38-year-old woman.

Sydney siege A police officer walks away from a robot outside Lindt Café on Martin Place in central Sydney, early Tuesday, Dec. 16, 2014. Australian security forces on Tuesday stormed the café, where several hostages were being held at gunpoint, in the dramatic denouement to a standoff that had dragged on for more than 16 hours. Photo: Reuters/Jason Reed

Monis, 50, was an Iranian refugee who was granted asylum in Australia in 1996. He was known in Australia before Monday’s attack for sending derogatory letters to the families of Australian soldiers who died in Afghanistan as part of U.S.-led operations there. He was also charged with 40 counts of sexual assault for actions during his time as a "religious adviser" in 2002, and charged with accessory to the murder of his ex-wife by his partner, Amirah Droudis.

Sydney cafe siege, Man Haron Monis The Australian government is looking into why it didn't take steps to stop Man Haron Monis from being in a position to carry out the Sydney siege terror attack. Photo: Reuters/ABC via Reuters TV

Prior to that, going by his previous name Manteghi Boroujerdi, he publicly urged the Australian government to allow his wife and child to come to the country. A brief 2001 interview with Monis about those actions can be read here.

Kamal Mousselmani, head of the Supreme Islamic Shia Council of Australia and considered the foremost Shia cleric in Australia, urged the police to investigate Monis in 2008 following his charges for the derogatory letters.

“From the way he writes his [fatwas], I don’t think he is Shia Muslim,” he told the Australian newspaper. “And there are no ayatollahs [which Monis had called himself] in Australia. We don’t follow, we don’t support and we don’t stand with anyone we don’t know. He’s not one of us.”

Monis’ now-defunct website included a number of letters he sent to Australian politicians, including Abbott, in which he accuses the government of levying false claims against him and denounces the Australian alliance with the United States.

Sydney cafe siege A bouquet lies inside a secured area at the scene of a hostage-taking on Martin Place, Sydney, after it ended early Tuesday, Dec. 16, 2014. Heavily armed Australian police stormed a café and freed a number of hostages being held there. Photo: Reuters/Jason Reed