A hostage who died during the Sydney cafe siege was killed by fragments of a police bullet as armed officers moved to end the 16-hour stand-off, an inquest has been told.
Katrina Dawson, 38, who was among 18 people taken hostage by a gunman last month, died after being hit by six fragments of the bullet that ricocheted off a hard surface, Jeremy Gormly, a lawyer assisting the coroner, told Glebe Coroner's Court. The bullet struck a major blood vessel and she quickly lost consciousness, he said.
The revelation came on the opening day of the inquest into the siege at the Lindt Chocolat Cafe, where horrific details of the attack unfolded publicly for the first time, including how the 34-year-old eatery manager was murdered while on his knees - the incident which forced police to storm the building.
Gunman Man Horan Monis forced Tori Johnson to kneel on the floor, then shot him in the back of his head with a sawn-off shotgun, Mr Gormly said. He is believed to have died instantly.
A police marksman witnessed Mr Johnson's killing, prompting officers to move in.
Monis, 50, an Iranian-born, self-styled cleric with a long criminal record, took the customers and workers inside captive and forced them to outline his demands in a series of online videos - including that he be permitted to speak to the prime minister and be delivered a flag of the Islamic State (IS) group.
The stand-off finally ended when police stormed the cafe in a barrage of gunfire to free the captives, killing Monis.
Authorities had previously refused to say whether the hostages died at Monis' hand or were caught in police crossfire.
The inquest is aimed at determining how they and Monis died, and whether the tragedy could have been prevented.
Mr Gormly warned in his opening address that the run-down of events he was giving was preliminary and based on his interpretation of the evidence he had seen so far.
The coroner will make the final declaration on how the hostages and Monis died.
"Rarely have such horrifying events unfolded so publicly," coroner Michael Barnes told the court.
"Overlaying the intense personal suffering on display were fearsome themes which called up wider and more far-reaching threats that understandably terrified many, even among those who only saw it from afar."
The inquest will look into how police managed the crisis, including whether snipers should have taken a shot at Monis through the windows.
"Questions concerning the use of police marksmen, whether to wait or act immediately and other options have been discussed in public; I anticipate evidence on all those matters," Mr Gormly said.
Mr Gormly gave a detailed account of how the siege unfolded on the morning of December 15.
Monis walked into the cafe at about 8.30am carrying a hidden pump-action, sawn-off shotgun.
He ordered and ate a piece of chocolate cake and drank a cup of tea before moving to another table near the door. After half an hour, he asked a waitress to bring him the cafe's manager.
Mr Johnson sat down with him and other workers soon noticed their manager appeared stressed by what Monis was saying. Mr Johnson then told a staff member to get the keys from his office, lock the door and remain calm.
Monis then put on a vest and a bandanna, brandished his shotgun and said he had a bomb in his backpack. He ordered everyone to move to one side of the cafe and forced several hostages to hold up a black Shahada flag with the Islamic declaration of faith written on it.
Under Monis' instructions, Mr Johnson called the police and said Australia was under attack by the IS group and that several radio-controlled bombs had been placed around the city - a threat that turned out to be false.
Some hostages managed to flee at different points throughout the ordeal. Monis first fired his gun after one group of hostages escaped; the bullet struck the wall above the main entry to the cafe.
The second bullet he shot was the one that killed Mr Johnson. He fired his gun three more times as police moved in, but none of those bullets hit anyone. He had another 21 cartridges in his pockets.
Two police officers fired 22 shots as they stormed the cafe. At least two police bullets or fragments hit Monis in the head and 11 others struck his body.
The inquest will examine Monis' mental health, his motivations for the attack and what, if any, terrorist associations he had. Mr Gormly said it did not appear Monis had established any contact with IS.
John O'Brien, one of the first hostages to escape, said listening to the summary of the horror he had lived through had been difficult.
"It was upsetting, very upsetting, for Tori Johnson's family," he said. "We were sitting in there and (it was) very emotional."
The inquest was adjourned for the day and the coroner has not yet set future hearing dates.
Meanwhile Australia's prime minister Tony Abbott has ordered a sweeping government review of the siege and the events leading up to it.
The review, expected to be released in the next week or two, will examine why Monis was out on bail despite facing a string of violent charges, including 40 counts of sexual assault and accessory to murder in the killing of his ex-wife.
It will also address how Monis, who did not have a gun licence, obtained a shotgun despite Australia's strict firearms laws.
Monis was on the Australian Security Intelligence Organisation's watch list in 2008 and 2009, but was later dropped from it.
The agency was tracking Monis because he had sent a series of offensive letters to the families of dead Australian soldiers.