Please note: This story contains reference to someone who has died.

Five years on from the fatal police shooting of 29-year-old Yamatji woman JC in the streets of Geraldton an inquest into her death will begin on Monday.

In 2019 First Class Constable Brent Wyndham shot and killed JC, the mother of a six-year-old boy, on the street while she was holding a knife and a pair of scissors and suffering from a mental health episode.

He was charged with murder but was found not guilty of murder and also manslaughter in a three-week trial in 2021.

At the time, JC's sister urged reforms to stop Aboriginal deaths at police hands and in custody, and nationwide protests were sparked.

Constable Wyndham testified in his trial that he believed JC was about to stab him when he opened fire, shooting her once in the abdomen.

Two weeks before JC was fatally shot she had been released from prison without ongoing mental health care or housing support.

Her foster mother, Anne Jones, who raised her from infancy, has been taking care of JC's son, now 11, since her death.

She told the ABC on the eve of the inquest that the boy "has been very badly impacted by the senseless death of his mother".

"He carries a lot of anger, confusion and fear about the death of his mother at the hands of WA Police," she said.

Eight police were called to the scene by a member of the public who has seen JC walking in the street allegedly carrying a knife and pair of scissors.

One of the officers, Adrian Barker, recognised JC from an earlier welfare check when she had called police herself seeking help.

Of the eight officers, only Mr Wyndham drew his firearm - shooting JC 16 seconds after exiting his vehicle. Mr Barker had not in that time told him of his earlier encounter with JC.

Mr Wyndham, now a Senior Constable, is still stationed in Geraldton, where many of JC's friends and family live.

"The fact that members of JC's family have to see Brent Wyndham still walking around Geraldton with a gun on his hip is appalling," Ms Jones told the ABC.

"Why is this police officer still in a position of power over our family in Geraldton?"

WA Police commissioner Col Blanch told the ABC that an internal investigation into the matter had resulted "in some disciplinary action" against Mr Wyndham, but did not elaborate on the details.

Western Australian coroner Ros Fogliani will oversee two weeks of hearings, with the first week scheduled to take place in Geraldton this week, followed by one week of hearings in Perth.

Ms Jones said the inquest was her family's last hope for answers and accountability.

She told the ABC she hoped WA Police policies around arresting First Nations people would be investigated as part of the inquest.

"The use of a powerful firearm on an Aboriginal woman who was known to the police arresting her to have a history of mental illness is a disgrace for the state of WA," she said.

"He had a taser on his belt — why didn't he use that before he shot her with such a powerful gun?"

At Constable Wyndham's 2021 Supreme Court trial, an expert gave evidence that police use-of-force protocols allowed for a taser or gun to be discharged when an officer reasonably suspected there was an imminent threat of grievous bodily harm.

The Court was told that under WA Police's use-of-force policy in place in 2019, officers had discretion as to what option they chose to deploy.

Ms Jones said before the inquest that Constable Wyndham should explain his actions to their family.

"For any good to come of her death, officer Wyndham needs to explain himself, and changes need to be made to the way WA Police arrest Aboriginal people," she said.