Constable Zachary Rolfe fatally shot Kumanjayi Walker, 19, three times as he resisted arrest in Yuendumu, northwest of Alice Springs, on November 9, 2019.
At the inquest into the incident, NT Assistant Commissioner Bruce Porter said that the force had been unable to confirm if police involved had been under the influence of drugs and alcohol.
"We're the only jurisdiction across Australia that does not have drug and alcohol testing for police," he said.
He clarified that he was not suggesting those involved in Walker's shooting were under the influence of drugs and alcohol, but that testing "is a tool that we are implementing to ensure that we do have a professional and ethical police force who are also obeying the law."
He was also questioned about the way the force had dealt with previous complaints about excessive use-of-force by Const Rolfe, who failed to turn on his body-worn camera in at least two incidents.
"It should have been dealt with by a supervisor at that time (...) that body worn was not activated," said Mr Porter.
NT Deputy Police Commissioner Murray Smalpage returned to the stand for his fifth day of questioning, and defended the police force.
He said the agency would "take the learnings from this inquiry (...) and adopt a bit of warts-and-all approach and try and find a way as an agency to be better to make sure that we try and prevent (this) ever happening again."
When asked why NT Police Commissioner Jamie Chalker had not appeared at the inquest, he said Chalker would "absolutely not" have been feasible.
Const Rolfe was found not guilty by a Supreme Court jury of Mr Walker's murder.
The inquest in Alice Springs continues, with other members of the NT Police Force and Territory Families expected to give evidence next week.
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