A belief that an incident in which Kumanjayi Walker ran at police with an axe was "being swept under the rug" was what prompted the officer charged with his murder to alert his superiors, a court has heard.
The jury in Constable Zachary Rolfe's murder trial heard directly from the defendant for the first time on Wednesday, as he took the stand as the first witness for the defence.
Constable Rolfe, 30, has pleaded not guilty to murder, as well as two alternative lesser charges, over the fatal shooting of 19-year-old Mr Walker in the central Australian community of Yuendumu in November 2019.
He joined NT Police the following year where he was deployed to Alice Springs before joining the "semi-tactical" Immediate Response Team (IRT) in mid-2017, the court heard.
Often addressing the jury directly, Constable Rolfe spoke with considered confidence about the training he received in becoming both a police officer and a member of the IRT, especially around what to do when confronted by someone with an "edged weapon".
"If someone is threatening us with an edged weapon, our first response was to go for our firearm unless that was impossible," he said.
"You shoot until the offender is incapacitated, no matter how many rounds that takes."
On November 7 of 2019, Constable Rolfe came into the station for a normal evening shift.
It was on this shift, he said, that he first found out about a young man from Yuendumu who was on the run from police for breaching parole, and then ran at two officers with an axe to avoid arrest.
Incensed by the body-worn camera footage of the incident that he watched from the police database, Constable Rolfe made it his mission to make sure his fellow officers were aware of Mr Walker.
"It showed to me an extremely, potentially deadly situation," he told the court.
"From my reading of the job, [the] initial job write-up, it seemed to me that this incident had - was being swept under the rug.
"It seemed that this is the kind of incident ... that we should all be alerted to, especially because Yuendumu is - it's three hours, but it's known that people from Yuendumu and Alice Springs generally go between fairly often.
"So this offender was, potentially, a risk to Alice Springs members."
He told his shift sergeant, and then called the then-boss of the IRT, Sergeant Lee Bauwens.
"I informed him of the incident, because I was in the mind that it was a potential job that IRT should have already been called out for," Constable Rolfe said.
Two days later, Constable Rolfe got the call asking him to join other members of the IRT on a deployment to Yuendumu, where it was believed Mr Walker was.
"I asked him [IRT acting officer-in-charge Sergeant Shane McCormack] specifically what our mission was," Constable Rolfe said.
"I asked him twice and he confirmed it was to arrest Kumanjayi Walker."
When asked whether he discussed this mission with his travel companion, Constable James Kirstenfeldt, on the three-hour drive, Constable Rolfe said there was "a brief conversation".
"The only comment that I can recall myself making is that we should've been sent out earlier. As in, days earlier," he added.
Finding Mr Walker in his grandmother's house around 15 minutes after being sent out for duty in Yuendumu that night, Constable Rolfe shot Mr Walker three times in the torso in response to Mr Walker stabbing him in the shoulder with a pair of scissors when he and his partner tried to make an arrest.
Mr Walker died around an hour after the shooting in Yuendumu Police Station, with Constable Rolfe being arrested and charged with his murder four days later.
Constable Rolfe will continue his evidence on Thursday.
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