The Yorta Yorta grandmother and respected member of the Victorian Aboriginal community had many passions: cooking, spending time with her family, and advocacy around Aboriginal issues, including deaths in custody.

But in December last year, her full life was cut short. Ms Day, aged 55, died after sustaining a head injury in a cell at Castlemaine police station, where she was held after being arrested for public drunkenness.

The Coroners Court of Victoria will on Thursday begin an inquiry into Tanya Louise Day’s death in custody.

In court, her grief-stricken family and their legal representatives, the Victorian Aboriginal Legal Service, will raise serious concerns about her treatment by police, public transport and ambulance workers.

Ms Day’s family wants to know exactly what happened in the hours between Ms Day’s arrest at Castlemaine train station, and the point when an ambulance was called to the police station because she was increasingly unresponsive.

Read more: Castlemaine death: abolish public drunkenness as a crime, says coroner 

It is unclear why her death was not publicised by Victoria Police, as often happens when someone dies while in police custody.

The Victorian Aboriginal Legal Service is calling for Victoria to abolish the offence of public drunkenness, and to fund community health alternatives like “sobering up” centres (which once existed in this state but lost funding).

Victoria and Queensland are the only states that have not abolished this offence. It was a key recommendation of the Royal Commission into Aboriginal Deaths in Custody almost 30 years ago, and numerous inquiries since.

And it is possible that had Ms Day been picked up in Moama, NSW – where she lived and where public drunkenness has been decriminalised – it's unlikely she would have been arrested and ended up in a cell.

“The tragic death of Aunty Tanya Day shows the need for immediate changes to the law in Victoria to prevent further deaths in custody,” says Wayne Muir, the head of the Victorian Aboriginal Legal Service.

“The injury she sustained while in police custody in Castlemaine should never have happened. It was the result of a litany of failures, beginning with the failure of successive Victorian governments to fully implement the recommendations of the royal commission.”

“Her injury and death a year ago is a shocking indictment of how the justice system in Victoria treats Aboriginal people.”

Tanya Day was born in Deniliquin and raised on Moonahcullah Mission, near the Victorian-New South Wales border.

She had five children: daughters Belinda Stevens, Kimberly Watson and Apryl Watson and son Warren Stevens. Another son, Luke, died from SIDS when he was four months old.

The trauma of her baby son’s death stayed with Ms Day, and her occasional heavy drinking was a way of coping, says her daughter Belinda.

Before her death, the 55-year-old had reduced her alcohol intake and was regularly going to the gym. She was eating healthy meals, and proudly posting her accomplishments on social media.

On December 5 last year, Ms Day left her home in Moama to catch a bus, and then a train, to Melbourne to visit her pregnant daughter, Kimberly.

The first her family knew something was amiss was a phone call from the police. They were told Ms Day had been sleeping on the train when a V/Line ticket officer woke her up to check her ticket, and found her difficult to rouse.

The inspector then called police, saying a passenger was intoxicated and “unruly”.

Police removed her from the train at Castlemaine and Ms Day was arrested for public drunkenness, her family was told.

They were confused. How could their mother have been “unruly” if she had been asleep?

“We’re concerned about racial profiling. If a white woman had been sleeping and not bothering anyone, it wouldn’t have been an issue,” says Belinda.

“And if it was difficult to wake her, and they were concerned, they should have had her medically assessed. Why was she arrested?”

The police told Ms Day’s children that police had a “duty of care” to not release Ms Day in an intoxicated state, Belinda says.

They were told Ms Day would be held for four hours until she had sobered up, then police would buy her a ticket and send her on her way to Melbourne.

Somewhat reassured, Ms Day’s family members called back a few hours later to check how she was.

A female officer told them she was concerned for Ms Day’s wellbeing because “it seemed as though she was getting drunker”, they say.

Warren, Ms Day’s son, was told by police his mum had a “slight knock to the noggin” but that she was OK and conscious, he says.

But she wasn’t OK. As Warren approached the police station, an ambulance drove past his car, with lights and sirens on. Inside – although he didn’t know it – was his mum.

“The police had all our numbers but they never made any effort to get in touch or provide an update. They downplayed everything,” says Warren.

This is the second time Tanya’s family has suffered the trauma of a death in custody.

Tanya’s uncle, Harrison Day, a skilled drover and horseman, died in custody in 1982 from an epileptic fit in an Echuca police cell, after he was arrested for an unpaid $10 fine for public drunkenness.

His death was examined by the Royal Commission into Aboriginal Deaths in Custody, which found supervision of the vulnerable prisoner was “grossly inadequate”, and recommended the offence of public drunkenness be abolished.

When Ms Day’s shocked children arrived at the hospital in Bendigo in the early hours of December 6, they found their mother lying unconscious on a hospital bed with a large bruise blooming across her forehead.

“Seeing her with our eyes was overwhelming,” says Apryl. “There were a lot of staff around her and they looked concerned and worried.”

Tanya Day never woke up. A scan revealed a massive bleed in her brain and she was flown by helicopter to St Vincent’s hospital in Melbourne, where she had emergency surgery to remove a section of her skull and relieve the pressure on her brain.

Her family say they were given inadequate and incomplete information about her condition, including conflicting advice that she had had an aneurysm, a stroke or haematoma.

Seventeen days after Ms Day was arrested, her children made the heartbreaking decision to remove her medical support in the intensive care unit.

A free spirit, who loved to dress in fluoro colours and sparkling clothes, Ms Day had been studying food and hospitality at TAFE in Echuca.

She was heavily involved in the local Aboriginal Njernda Cooperative and the Moama Lands Council, and was a founding member of the community childcare centre.

A spokesperson for Victoria Police said it would not make comments on a matter before the Coroner.

The Age