Four men are dead, a woman has been wounded and the alleged gunman responsible is in hospital after an "insane" bloody rampage across five different locations in Darwin.
The 45-year-old suspected gunman, who was on parole, was arrested after being on the run for about an hour following the mass shooting in and around a hotel in Darwin's CBD on Tuesday night.
Detectives will on Wednesday start piecing together the sequence of events, including the motives of the shooter, who's been named as Darwin local Ben Hoffmann.
The incident started with reports of a man firing shots at Finnis St at about 5.50pm just outside the Darwin CBD, with the four deaths occurring at the nearby Buffalo Club, Gardens Hill Crescent, the Palms Motel and Jolly Street.
He also tried to enter the Peter McCauley Centre police station to possibly hand himself in, then phoned a duty superintendent who did a "magnificent job in negotiating with him" before the arrest, Police Commissioner Reece Kershaw told reporters.
A group of about a dozen men who were friends and relatives of a man who died at the Palms Hotel gathered outside after the shooting and many were in tears.
Darwin local Matthew James, who knows the shooter was standing in a carpark nears the Palms when it all began.
He described the scenes to breakfast radio show 'Roo & Ditts' for Triple M Adelaide: "A guy came up to me with this woman in his arms, she couldn't walk, she's been shot, she was bleeding. She was frantic, screaming out she'd been shot."
Listen to Matt describe the scenes and the gunman here:
Witness, Leah, also spoke of the shooting - saying they initially thought the noise was fireworks - to Moonman In The Morning on Triple M Sydney.
"The gunman was talking down the road with a pump action shotgun in his hand. The police came over from the petrol station... a man told us then they had been in a hotel room minding their own business and the gumnan had came looking for someone else and he'd shot the door."
Leah describes horror scenes in Darwin:
The alleged shooter is an outlaw motorcycle gang member, well known to police with a criminal history, and the incident is not believed to be terror-related, according to police.
He was released from prison on parole in January after serving at least a year and was wearing an electronic monitoring bracelet, Mr Kershaw said.
"He is an individual who is well known to police and has a number of interactions - adverse - with the police force," he said.
"We're still trying to establish the intent and the motivation behind this but all I can say is that, sadly, people have lost their lives this evening."
The alleged shooter is in hospital, under guard. The Prime Minister Scott Morrison assured the public this was not a terror attack.