The New Zealand man who was killed in the Darwin shootings stabbed his attacker before being gunned down.
Robert Courtney, a 52-year-old security guard who worked at Mindil Beach Casino, was known to alleged gunman Ben Hoffman, according to police.
The pair fought at a scrap recycling plant, before Courtney stabbed Hoffman and was shot dead, reports The Age.
Northern Territory police commissioner Reece Kershaw said it was "a possibility," that Courtney's courageous final actions slowed the alleged gunman and forced him to hand himself in.
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"That's probably speculating but [Hoffman] did have to undergo surgery in hospital for those wounds," he said.
The alleged gunman knew two of the four men he is accused of murdering, reports The Age.
He opened fire at around 5.30pm at the Palms Motel on Tuesday evening, killing 33-year-old Hassan Baydoun and injuring a woman.
From there, it's alleged Hoffman travelled to Gardens Hill where he shot and killed 76-year-old Nigel Hellings.
Then, he went to Stuart Park and shot 57-year-old Michael Sisois, who he had worked with previously as a roofer, in a car park outside a bar.
Courtney, his final alleged victim, was killed on Jolly Street at around 6pm.
An hour after he opened fire, at roughly 6.44pm the alleged shooter was apprehended and tasered by police. He was then arrested and taken to hospital for his stab wounds.
Police are awaiting toxicology reports to see if Hoffman was under the influence of drugs at the time of the attacks, reports The Age.
Hoffman was transferred from hospital to the Darwin watch house on Thursday, and then charged with four counts of murder as well as recklessly endangering serious harm and criminal damage.