The motivators, and indeed, the details are sketchy, but the suspect is believed to be in the company of the police.
The group then worked together, according to interviews in The Age, to overcome the knife-wielding man. Fuller described the weapon as a butcher's knife.
"The threat to the community has been negated".
New South Wales police said in a statement that a man was arrested, and that a woman was taken to a hospital in stable condition.
No other serious injuries have been reported. "I can say he does have a history of mental health, but at this stage, I can't expand on that", said Fuller.
"Officers. are on the scene and will be conducting inquiries as to whether this incident is linked to an earlier stabbing at a hotel", a police spokeswoman told AAP.
2GB reporter Tamara Wearne spoke with Tom Elliott from the scene.
Another resident said police only told her a woman was dead and she'd have to return later.
Lee Cuthbert, Paul O'Shaughnessy and Luke O'Shaughnessy, all from Greater Manchester, were working in an office nearby when they heard the commotion outside and ran out to help. He'd already stabbed one woman at a nearby hotel, police later said, and tried to attack others in the busy commercial district on Tuesday.
Video footage on Twitter showed a young man running across a city intersection and jumping onto the hood of a vehicle, waving what appeared to be a knife. "And I want to acknowledge that".
According to the BBC, video footage shows the suspect shouting "Allahu Akbar" and "shoot me", jumping on a auto with a knife, as another man confronts him with a wicker chair.
The man was in custody and expected to be charged with homicide, assault and, depending on the outcome of the investigation, potential terrorism offences, Fuller said. "I saw people running so I ran towards him with a few other guys", Jack Huddo said on Facebook. They not only saved lives, but they made sure this lunatic will get what's coming to him ... we hope.
"Members of the public are urged to avoid the area".
Paul Walker, a Channel Seven cameraman was on the scene and followed the chase through the city filming the arrest near the corner of Carrington and Wynyard streets in Wynyard.
As Baghlani continued to drive through the city, he saw the man being chased by firefighters and members of the public "with chairs and everything they could get their hands on".
"To approach a person with a mindset of obviously what this person did, with clear evidence of a stabbing previously, these people are heroes".
Prime Minister Scott Morrison said, "The violent attack that took place in Sydney this afternoon is deeply concerning".
Prime Minister Scott Morrison commended "the courageous actions of those who were present" and said on Tuesday that his "thoughts are with all those who have been impacted by this violent attack".