NT cop's murder trial evidence questioned

A Northern Territory policeman's evidence before he was acquitted at trial of murdering an Indigenous teenager may have been contaminated, a top-ranking officer says.

Constable Zachary Rolfe was found not guilty in March of intentionally killing Kumanjayi Walker, 19, after he shot him three times during an arrest in Yuendumu, northwest of Alice Springs on November 9, 2019.

Two days after the Warlpiri man died, Const Rolfe ignored police orders and met with colleagues also involved in the shooting for a barbecue in Alice Springs, an inquest into Mr Walker's death heard on Monday.

Assistant commissioner Travis Wurst agreed with counsel assisting Peggy Dwyer that the social gathering was inappropriate and in contravention of police orders "particularly in relation to Const Rolfe, who hadn't provided a statement" to investigators about the incident.

He also agreed it had the potential to "contaminate" the version of events that Const Rolfe eventually gave at his trial.

"To this day we don't know the extent to which that contaminated his evidence," Dr Dwyer told the coroner in Alice Springs on Monday.

"It's a fair assumption to make," Mr Wurst responded.

The court also heard Mr Wurst approved Const Rolfe's deployment to the outback community Yuendumu with his fellow immediate response team members but said it was to help local officers with general duties, not arrest Mr Walker.

He said he understood the plan was for local officers to arrest Mr Walker with the assistance of an Aboriginal police officer and elders following a funeral in the community.

"What I was approving was members of the IRT who were all general duties members to attend to assist at Yuendumu."

Mr Wurst said he didn't consider the deployment high-risk and agreed there was no justification for the team to take tactical weapons, including an AR15 assault rifle and a shotgun, to the community of about 800.

He said it would have been confronting and confusing for the community to see the officers patrolling with the weapons.

"It wasn't appropriate," he said.

After the shooting, Mr Wurst took control of the police response from Darwin. He was responsible for not letting family members comfort Mr Walker as he lay dying on the floor inside the local police station, saying it was a "troubling" decision.

"I know the community were hurting and are hurting to this day," he said.

But he said there were concerns family members may have become overly emotional if allowed into the station.

He was also worried about the seven officers inside the station who were "tense" and under pressure amid concerns about how the community may react to the shooting.

"My direct advice from (officers in Yuendumu) is people were armed. There was a large gathering, up to 200 people and they were angry and upset," he said.

"(One of the officers inside the station) told me he had never been so scared for his life."

Mr Wurst was also behind the decision not to tell Mr Walker's family and the broader Yuendumu community that he had died until November 10.

"I've grappled with that ever since, knowing full well that the cultural responsibilities of the family on the passing are a complete juxtaposition to ... how we managed that particular scenario," he said.

"It's something I'll have to live with."

He said he had a genuine concern that if the community learned Mr Walker was dead it could react violently against the officers and more people may have died.

"If we had communicated with the wrong person by phone and that information had've been misconstrued or misused, that was the potential outcome ... I was grappling with," he said.

The hearing continues on Tuesday.