A Northern Territory policeman on trial for murdering Kumanjayi Walker has denied being obsessed with a video of the Aboriginal teenager before he fatally shot him.
Constable Zachary Rolfe, 30, has pleaded not guilty to murdering Mr Walker, 19, during a failed arrest attempt in Yuendumu, 290km northwest of Alice Springs.
He fired three shots into the teen's back and torso on November 9, 2019 after he was stabbed with a pair of scissors.
The former soldier, who served in Afghanistan, has said he first became aware of Mr Walker two days earlier when the teen was listed as an arrest target for breaching his parole conditions and assaulting two police officers.
Rolfe also viewed body-worn camera footage repeatedly of a so-called "axe incident" involving Mr Walker in the following days at the Alice Springs police station.
It showed the teen violently threatening two officers in Yuendumu on November 6 to evade arrest.
Neither officer was injured but Rolfe told the Supreme Court in Darwin on Friday Mr Walker was "lucky he did not get shot that day".
Prosecutor Philip Strickland SC accused the constable of becoming obsessed with the video in the lead-up to the shooting.
"No," Rolfe replied in a terse exchange on his third day in the witness box.
The constable also denied being "fixated".
"You were certainly preoccupied," Mr Strickland suggested.
"No," Rolfe replied.
"You had seen it by then on multiple occasions, hadn't you?" Mr Strickland said.
"Correct," Rolfe replied.
"You hadn't become preoccupied with the idea of tracking down Kumanjayi Walker?" Mr Strickland asked.
"No," Rolfe replied again.
But Rolfe did agree that his supervisors had not ordered him to view the video.
Rolfe has previously told the court that he believed Mr Walker's axe-incident had been "swept under the rug" and should have been taken more seriously by his superiors.
Earlier the court was told that after Rolfe served in Afghanistan with the Australian Army he tried to join the elite Special Air Service Regiment and the NT police Tactical Response Group
He also applied to join the Australian Defence Force Commando unit and paid for a four to five-week private US military training course with Trojan Security International in Arkansas.
"In between the military and police I travelled to America for private training out of my own pocket," he said on Friday.
"I wanted to upskill myself and continue to improve myself so I could eventually join the police."
The Crown has conceded the first shot, which was fired while Mr Walker was standing and resisting arrest with Sgt Eberl, was justified.
But it says the second and third shots, which are the subject of the murder charge, went "too far".
Mr Walker died about an hour after the second shot ripped through his spleen, lung, liver and a kidney.
The trial continues.
