Kumanjayi Walker planned to hand himself in to police the day after Constable Zachary Rolfe allegedly murdered him during a failed outback arrest, a jury has been told.
Warlpiri elder and Yuendumu community leader Eddie Robertson says the 19-year-old agreed to surrender to police on November 10, 2019.
"I asked Kumanjayi if he can come to the police station and give himself in," he told Rolfe's trial in the Northern Territory Supreme Court on Wednesday.
"He nodded his head and said: 'Yep'."
Mr Robertson - who was Mr Walker's partner Rakeisha's grandfather - said he had spoken to the officer-in-charge at the Yuendumu police station, Sergeant Julie Frost.
The pair had agreed Mr Walker would be taken into custody after his great uncle's funeral which was initially planned for November 8 but moved to November 9.
"I was going to ask him to come with me to the police station," Mr Robertson said.
He did not get the chance.
Mr Robertson's phone rang while he was at the cemetery with the news Mr Walker had been shot.
Police escalated the order to arrest him after he threatened two other policemen with an axe on November 6.
Those officers had been trying to arrest the teen for breaching a court order when he removed his electronic monitoring device and fled an Alice Springs alcohol rehabilitation clinic about a week earlier.
Three days later, Rolfe and three fellow response team members were ordered to arrest Mr Walker early on November 10 but they failed to follow the plan.
About 45 minutes after arriving in the community of about 800 on November 9 Rolfe shot the troubled teen three times after he stabbed the constable with a pair of scissors in the shoulder.
In the minutes before that, Rolfe and his team went to Eddie Robertson's home where they spoke to his son Ethan Robertson.
On Wednesday Ethan Robertson told the court he tried to call his daughter Rakeisha to tell her the police were looking for Mr Walker.
"They were just walking to a disco at the youth program," he said.
"There was no answer. I was going to tell my daughter they were looking for Kumanjayi."
The response team then went to Mr Walker's grandmother Margaret Brown's house, where Rolfe and his partner Constable Adam Eberl scuffled with the teen as they attempted to arrest him.
Mrs Brown raised Mr Walker and said she spoke to him about the so-called "axe incident".
"He said he was protecting himself from police," she said.
Rolfe has pleaded not guilty to murdering Mr Walker, saying he was doing his job in "good faith" and defending himself and a colleague against a violent criminal.
Prosecutors have conceded the first shot, which was fired while Mr Walker was standing and resisting arrest, was justified.
But it says the fatal second and third shots when Mr Walker was laying on the ground went "too far".
Mr Walker died at 8.36pm from injuries sustained from one of those shots, which the Crown says were not legally justified because Mr Walker was "effectively restrained".
Earlier, the court was shown video of Rolfe's colleague Constable James Kirstenfeldt telling investigators soon after the shooting that their team had "formulated, like, our own arrest plan".
The evidence was played for the jury after Const Kirstenfeldt repeatedly denied Sgt Frost had shown the team an approved plan to arrest Mr Walker at 5.30am on November 10.
He was forced to accept that he had seen Sgt Frost's plan after the same video showed him saying he had "skimmed" or read through it.
The trial continues on Thursday.
