A former Northern Territory police officer has lost an appeal and can be forced to answer a coroner's questions about the fatal shooting of an Indigenous teenager.
Ex-constable Zachary Rolfe shot Kumanjayi Walker three times during a bungled outback arrest in Yuendumu, northwest of Alice Springs, on November 9, 2019.
He may now be required to answer uncomfortable questions about racist text messages an inquest into Mr Walker's death was told he sent.
He is also likely to be asked about the night he killed the 19-year-old, his alleged misuse of police body-worn cameras, excessive use of force and a falsified NT police recruitment application.
Mr Walker's family welcomed Wednesday's Court of Appeal ruling, despite being frustrated by the constant disruptions in their "journey for answers".
"There is no moving forward or justice without the full truth and accountability,” his cousin Samara Fernandez-Brown said.
The Northern Aboriginal Justice Agency said the judgment was an important step towards holding police accountable for the deaths of Aboriginal people in their custody.
“Kumanjayi Walker’s families and communities searching for answers deserve to know the full truth as to how their loved one died," principal legal officer Nick Espie said.
"The coronial process can now hear all relevant evidence and also consider community-led solutions for how to prevent future deaths in custody."
The inquest into the Warlpiri man's death has been repeatedly disrupted by legal stoushes about whether Mr Rolfe and another officer had the right to refuse to provide evidence.
Coroner Elisabeth Armitage previously determined witnesses could not decline to answer questions by invoking the penalty privilege, which Mr Rolfe did when he first appeared at the inquest in November.
His counsel had argued the coroner could not protect him from potential disciplinary action from his then-employer stemming from his evidence and the penalty privilege protections remained available to him as a common law right.
The coroner's ruling was initially upheld by the NT Supreme Court and was reaffirmed by the Court of Appeal.
It pointed to changes to legislation in 2002, which gave coroners the power to protect witnesses from self-incrimination
In such circumstances, the court found it would contradict the operation of coronial legislation if penalty privilege against disciplinary action was to remain in force.
"The requirement to answer questions in coronial proceedings is directed in large part to the conduct of public authorities and should be similarly unfettered," the appeal court ruled.
"The continued operation of a penalty privilege after the abrogation of the privilege against self-incrimination would contradict or diminish the operation of the coronial legislation and the achievement of its purposes."
Mr Rolfe's legal team told AAP it was reviewing the appeal court decision and would "determine its implications".
In March last year, a Supreme Court jury found Mr Rolfe not guilty of murdering Mr Walker, causing outrage in the Indigenous man's grieving community.
The inquest into the shooting is due to resume in October when the former officer is scheduled to return to the witness box.
He took personal leave from the force in August last year and in February left Australia after writing a 2500-word open letter defending his character and criticising NT police and its commissioner over how they handled the inquest.
Mr Rolfe was dismissed from the force in April for disciplinary reasons.
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