What we do know

The siege is over. Police stormed the building after hostages began running from the cafe just after 2am. Multiple shots were fired.

Three people are confirmed dead. One deceased person is the gunman, aged 50.

The other two deceased were hostages: a 34-year-old man, Tori Johnson, who was the Lindt store manager and Sydney barrister Katrina Dawson, aged 38.

A policeman was also shot in the face. His injuries are not critical.

NSW Police have launched a critical incident investigation.

The gunman is Man Haron Monis. He was out on bail for numerous charges including accessory to murder and sexual assault. He is not believed to have any formal links to any terror organisation.

Monis was a "self-styled cleric" with no role in any mosque. The gunman had previously sent letters to the families of Australian soliders killed in Afghanistan and to political leaders, including former prime minister Kevin Rudd and Prime Minister Tony Abbott.

He was granted asylum in Australia in 1996. He was born in Iran.

There were 17 hostages inside the Lindt cafe. Five escaped on Monday. Six escaped uninjured just after 2am on Tuesday. Two of the remaining hostages were confirmed dead.

NSW Police media have given the following information on those wounded:

- A 75-year-old female who received a gunshot wound to the shoulder – stable condition.

- A 52-year-old female who received a gunshot wound to the foot – stable condition.

- A 43-year old female with a gunshot wound to the leg – stable condition

- A 39-year-old male who received a minor facial injury due to gunshot – treated at hospital and discharged. [This man is a police officer.]

- A 35-year old pregnant female assessed for health and welfare purposes - stable.

- A 30-year-old pregnant female assessed for health and welfare purposes - stable.

Videos emerging on Tuesday morning have hostages being forced to make statements of demands with claims that Monis was associated with the Islamic State terror group.

The NSW Premier Mike Baird has invited members of the public to lay floral tributes.

People wishing to lay a floral tribute to the victims are invited to do so at Martin Place. — Mike Baird (@mikebairdMP) December 15, 2014

What we don't know

How the crescendo was reached. We know one man was seen running from the cafe just after 2am. Several others ran out soon after, before the sound of gunshots. There is speculation that the hostage group had been put in two sections. One group may have escaped, which may have precipitated gun fire.

Police Commissioner Andrew Scipione said: "I understand there was a number of gunshots that were heard, which caused officers to move straight to a what we call an EA, an emergency action plan, and that caused them to enter."

Channel 9 is reporting that the killed Lindt store manager, Tori Johnson, was attempting to wrestle a shotgun from Monis when the gunman "began to nod off". This is unconfirmed.

Who fired first. It is not yet known whether police started firing or were responding to the gunman firing shots. Commissioner Scipione said these details will be the subject of a critical incident investigation.

What specifically motivated the gunman. We do know he had been fighting a long and unsuccessful battle over his conviction for sending offensive letters to the families of dead Australian soldiers between 2007 and 2009.

How it was that Man Haron Monis was out on bail.

How Monis gained access to a gun.

It is not known if Monis had any links with the Islamic State terror group, despite claims made in videos.

There are reports the gunman lost an appeal at the High Court on Friday. Details unknown at 8am Tuesday.