A Northern Territory policeman who shot dead an Indigenous teenager has refused to answer controversial questions at his inquest over fears they could expose him to disciplinary action.
Constable Zachary Rolfe shot Kumanjayi Walker three times during a bungled arrest in Yuendumu, northwest of Alice Springs, on November 9, 2019.
He's since returned to work with the NT police force in a Darwin office because he's been "banned from all police stations".
The 31-year-old was summoned to give evidence on Wednesday at the Alice Springs inquest but invoked the penalty privilege when counsel assisting Peggy Dwyer questioned him about a racist text message sent to another officer.
"I wish to exercise my right and claim the penalty privilege on the basis my answers might tend to expose me to penalty," he said.
In the text, Const Rolfe uses a derogatory term to refer to Aboriginal Australians.
"Nah Brah, just slightly annoying. Haha. C**ns man," he wrote when another officer asked him if he'd had a "rough afternoon" on the job.
Const Rolfe also claimed privilege over other allegedly racist messages found on his phone and questions about the night he killed Mr Walker.
He confirmed he would also invoke privilege over evidence related to his alleged misuse of police body-worn cameras and excessive use of force.
All told, Const Rolfe said he would claim privilege for 14 categories of evidence, including a video found on his phone and shown to the court of an incident outside an Alice Springs bar.
NT Police Force lawyer Ian Freckelton KC told the inquest the 14 categories were matters that had been the subject of disciplinary proceedings against Const Rolfe and all but four incidents had been finalised.
Const Rolfe's lawyer, Luke Officer, said the finalised disciplinary proceedings could potentially be reopened as he made a case for the coroner recognising the claim of privilege.
He also told the court the NT attorney-general had objected to Const Rolfe joining a legal challenge by two other NT police officers against Coroner Elisabeth Armitage's earlier ruling that the NT Coroner's Act modified the ability of a witness to claim privilege.
Ms Armitage declined to make a ruling about Const Rolfe's 14 categories of evidence and instead temporarily stood the officer down from the witness box until after the Supreme Court challenge had been heard.
Before claiming privilege, Const Rolfe told the inquest about his time as a student at grammar school in Canberra and his military service with the Australian Defence Force.
He also answered questions about the cultural training he had received when he joined the NT police in 2016, saying: "We were taught to respect everyone".
Const Rolfe shot Mr Walker in the back and torso during a scuffle in a darkened room as the Warlpiri man resisted being handcuffed.
The 19-year-old died about an hour later on the floor of the Yuendumu police station as officers fought to save his life.
Const Rolfe was later charged with Mr Walker's murder and acquitted in March after a five-week trial that left the Warlpiri community calling for justice.
He returned to work in July but he's been on sick leave since August and said he was unlikely to return to work in the near future.
The inquest has previously heard Const Rolfe was banned from applying to join the Queensland Police Force for a decade for failing to disclose violent behaviour on his job application.
He also failed to disclose that he had pleaded guilty to stealing while he was a soldier in 2012 when he applied to the NT Police Force and told his former fiancee he wanted to kill people.
NT police psychological testing revealed that Const Rolfe had above-normal aggression levels and was less likely to accept responsibility for mistakes than other people.
The inquest continues on Thursday.