Constable Rolfe's defence told the jury the prosecution had "not come close" to producing a case against his client, who he said had acted reasonably in the 2019 shooting of Mr Walker during an attempted arrest.

Both the prosecution and the defence made their closing addresses to the jury in Darwin on Wednesday, with deliberations set to begin on Thursday.

Crown prosecutor, Philip Strickland SC, took the jury back through the evidence presented to them over the past month from forensic pathologists, police officers, and Constable Rolfe himself.

Mr Strickland told the court the central issue of the case was whether or not the second and third shots fired by Constable Rolfe were legally justified, with the Crown needing to overcome three defences that can be used by Constable Rolfe: self-defence, acting in the course of duty and acting in good faith in his duty as a police officer.

He said the Crown case was that Constable Rolfe had lied in his evidence about seeing Mr Walker stabbing his then-partner, Constable Adam Eberl, after Constable Eberl had wrestled Walker to the floor, which is when Constable Rolfe fired the second and third shots.

"We say that, on the evidence before you, you can conclude the following; that the accused did not see Kumanjayi Walker stabbing Constable Eberl in the chest or neck area when he was on the mattress, or when he was standing up; and, secondly, that the accused did not fear for Constable Eberl's life when he fired shots two and three," Mr Strickland said.

"The Crown case is that the evidence that the accused gave in court, that he did have those beliefs, was a lie, and the accused lied to justify the unjustifiable; namely, the fatal shooting of Kumanjayi Walker."

Mr Strickland also argued that Constable Rolfe lied about the fact that Mr Walker reached for his gun during the scuffle before the shooting, noting Constable Rolfe did not tell any of his colleagues about it and that body-worn camera footage appears to show that Mr Walker's left arm, the one Constable Rolfe alleges reached for his gun, was restrained at the time.

"That evidence, that his left hand, that Kumanjayi Walker's left hand is on the Glock, is a lie," he said.

"And it's extremely damaging to your assessment of his credibility, that he believed that Constable Eberl's life was in immediate danger, at the time he fired shots two and three."

In his closing address that followed, Constable Rolfe's defence lawyer David Edwardson QC told the jury the prosecution had "not come close" to producing a case against his client.

"With the exception of Detective Senior Sergeant Andrew Barram, each police witness only confirmed the truth of the matter; what Zachary Rolfe did was not only what he was trained to do, but his response by firing all three shots was reasonable and proportionate under the circumstances," Mr Edwardson said.

He went on to attack the police investigation of the case, as well as three key prosecution witnesses; Yuendumu Officer-In-Charge Sergeant Julie Frost, forensic pathologist Dr Marianne Tiemensma and veteran NT Police officer Detective Senior Sergeant Andrew Barram.

Detective Senior Sergeant Barram, in his evidence, told the court Constable Rolfe's choice to fire the second and third shots were not reasonable or necessary or in accordance with his training.

Mr Edwardson said, "This case is tragic - a young man lost his life and a young brave police officer has been charged with the most serious charge ... without any proper investigation. And that...is a disgrace."

Mr Edwardson said, in choosing to fire the second and third shots into Mr Walker, his client acted in a way that was "not only appropriate, but frankly, just plain common sense".

"He deployed a lethal weapon, namely the scissors, he stabbed Zachary Rolfe and then turned his attention to Constable Eberl," he said.

"If Mr Walker had hit his carotid artery, Zachary Rolfe would be dead.

"In many respects, he [Mr Walker] was the author of his own misfortune."

Constable Rolfe has pleaded not guilty to murder, as well as alternative charges of manslaughter and violent conduct causing death, over the fatal shooting of 19-year-old Mr Walker during an arrest gone wrong in November 2019.

Presiding Justice John Burns is set to do his summing up of the case to the jury on Thursday morning before they are sent out for deliberation.