Former Northern Territory Police constable Zachary Rolfe will answer questions about the night he shot dead an Indigenous man, following evidence of the ex-officer’s unravelling mental health and racist text messages.

Mr Rolfe shot Kumanjayi Walker, 19, three times while on duty in the remote community of Yuendumu in November 2019 and was acquitted of murder at a five-week trial.

An inquest into Mr Walker’s death is due to hear a third day of evidence from Mr Rolfe on Wednesday. He has already been questioned over a stream of text messages, his use of force, and his falsified police application.

In a series of SMS released to media on Tuesday night, Mr Rolfe described his ongoing mental health issues in the months before Mr Walker was shot dead.

“I think I’m run down and burnt out from work bullsh*t atm, I’m feeling real sad and sorry for myself right now,” reads one message from eight months before the fatal shooting.

In another text, he told a female friend: “I needed some violence to re-centre my head. I know that’s weird”.

Other texts included homophobic slurs, racist terms and misogynistic comments about police colleagues.

On Tuesday, the inquest was also shown footage from an arrest in 2019 in which Mr Rolfe and another officer crashed into a suspect, causing him to ricochet into a wall, resulting in a head injury.

Mr Rolfe said he was acting in response to seeing the man headbutt and punch a woman and conceded his actions during the incident were affected by anger as a result of witnessing a suspected domestic violence incident.

Later, Mr Rolfe messaged a paramedic he was close with about the incident, boasting he “mashed some dude’s face up against a wall”.

Mr Rolfe denied he was using violence as a way of coping with the pressures of the job after a question from counsel assisting the coroner Peggy Dwyer, instead claiming it was a way of “venting frustrations”.

“Obviously, that job is one of those jobs that I was talking about before that does create anger seeing a woman get assaulted by the main person in her life who should be protecting her,” he said.

The inquest was told Mr Rolfe was suffering from insomnia while working in Alice Springs and on occasion would self-medicate with cannabis edibles.

Mr Rolfe said it was common for officers to deal with mental health issues on their own while some would use stress leave to “fudge the system”.

Dr Dwyer said the abuse of the system had to stop “because it makes it so much more stressful for other officers on the ground”.

As a result of Mr Rolfe’s inquest evidence which includes claims of racism in the force, NT Police has announced plans to review its culture.