The chaos started when 3AW was flooded with calls from people at the scene who had witnessed a vehicle "bursting into flames" just after 4pm on Friday.
A police officer finds room to shoot the suspect and the man drops to the floor clutching his chest.
We'll keep an open mind as to whether there's any link. One of the victims later succumbed to the injuries, while two others are still receiving treatment.
The man crashed a utility at the corner of Bourke and Swanston streets before exiting the vehicle as it caught alight, and then attacking nearby passers by.
Witnesses have described the horror and chaos in Melbourne's Bourke Street Mall as a knife-wielding man crashed into pedestrians, before stabbing three shoppers, leaving one dead.
However, video posted to Twitter and broadcast on television showed a man repeatedly swinging an object at two police officers.
"We thank our police, those who came to assist them", he said.
The officers were immediately confronted by a man brandishing a knife and threatening them.
The centre of Melbourne's CBD remains in lockdown after horrific scenes unfolded about 4.30pm, sending Friday afternoon shoppers and commuters running for safety.More news: Tia Mowry Mourns Death of Tamera's Niece in Thousand Oaks Shooting
The police and State Premier Daniel Andrews asked people to avoid the area.
They said the suspect, who was hospitalised in a critical condition, had no known links to terrorism. Police were investigating the incident in Melbourne as suspected terrorism, and they were re-evaluating security plans for upcoming public events.
Clayton said investigators did not believe there were any other assailants.
"A small number of people are being treated for stab wounds".
If members of the public have images or video footage that may assist police with their investigation into the Bourke...
The attack occurred on Bourke Street in the central downtown area.
A witness who gave his name as Markel told Australian Broadcasting Corporation radio: "Bystanders were yelling out "just shoot him, just shoot him". Most sat in three rows of chairs, before being called to one of six tables set up by police. Hundreds of people watched from behind barricades as police tried to apprehend the attacker.
Counter-terror officers have swooped on the scene.