Shots fired by a police officer accused of killing Aboriginal teenager Kumanjayi Walker were “not reasonable”, court has heard, as a marathon trial expected to last up to one month begins.

The long-awaited trial of police Constable Zachary Rolfe, 30, who is charged with murdering Mr Walker in Yuendumu, opened on Monday in the Northern Territory Supreme Court.

Mr Walker died aged 19 after being shot three times during an attempted arrest in the remote community in November 2019.

Constable Rolfe has pleaded not guilty to murder, as well as lesser charges of manslaughter and engaging in a violent act causing death.

On Monday Prosecutor Philip Strickland opened the Crown’s case against Constable Rolfe, running the jury through the events beginning with the first shot allegedly fired at Mr Walker.

He noted that the first shot, allegedly at Mr Walker while he was standing, was not fatal.

“Our community is still shaking, wondering what’s going to happen to our kids’ future,” Ned Hargraves

Mr Strickland told court after the first shot Mr Walker either fell or was taken to the ground by Constable Rolfe’s partner, and 2.6 seconds later a second was fired, followed by a third shot 0.5 seconds later.

The prosecution said Mr Walker was lying on a mattress with Constable Rolfe’s partner on top of him when the second and third shots were fired, with the third fired “point blank”.

Mr Strickland told court Constable Rolfe had limited experience with remote Indigenous communities, and was there as part of a response team from outside the community.

Constable Rolfe’s defence did not make remarks on the first day of the trial, and Mr Strickland will continue the prosecution’s opening remarks on Tuesday.

It is understood the officer’s case will argue he acted in self defence because Mr Walker was holding a pair of scissors at the time and had stabbed the officer in the shoulder.

They are also expected to argue his actions were in good faith during the course of his duties as a police officer

Mr Walker’s family and several Elders travelled more than 1,500 kilometres from Yuendumu to Darwin to witness court proceedings, and the public gallery was at its maximum capacity allowed under COVID restrictions, about 50 people.

Senior Yuendumu Elder Ned Hargraves told NITV the family was relieved the case was finally being heard.

“We have waited a long time. We’ve come a long way. We want justice for our family… We are still grieving the loss of a loved one (that) was taken away from us. We are still holding those bad feelings about what took place,” he said

“Our community is still shaking, wondering what’s going to happen to our kids’ future.”

Constable Rolfe told media outside the court house he was “feeling very confident” before the trial began.

The trial has been subject to a number of delays, including travel restrictions caused by COVID, the September retirement of the judge who was to preside over the case, and a late legal battle in the High Court last year.

Trial days have been shortened as a precaution against COVID-19, meaning the trial will run for up to four weeks.