Warning: This story contains details that some readers may find disturbing.
First Nations readers are advised that this story contains images and names of people who have passed away.
A man's predatory and disgraceful behaviour that resulted in the deaths of two Indigenous teens was not properly investigated, in part due to racial bias among police at the time, a coroner has found.
Mona Lisa Smith, 16, a Murrawarri and Kunja girl, and Jacinta Rose "Cindy" Smith, 15, a Wangkumara girl, died in the early hours of December 6, 1987.
READ MORE: Crown gets green light to run Sydney casino
The vehicle they were travelling in rolled on the Mitchell Highway, between Bourke and Enngonia in outback NSW.
At the wheel of the vehicle was then-40-year-old Alexander Grant, who had picked the girls up after offering them a lift home.
But instead of taking them there, he "plied" them with alcohol before taking them out onto the highway, a coronial inquiry concluded on Tuesday.
Following the crash, in which the girls suffered catastrophic internal injuries, evidence suggested a mostly uninjured Grant "horrifyingly" sexually interfered with an already dead Cindy.
In delivering the findings 36 years after the girl's deaths, NSW State Coroner Teresa O'Sullivan said their families had been vindicated in pushing for answers despite being repeatedly dismissed.
READ MORE: The bush superfood growing in our backyard for over 140 million years
The initial police investigation suffered from "very serious deficiencies" impacting the likelihood of any future criminal conviction, including failing to collect key evidence from the crime scene, O'Sullivan concluded.
Investigators initially believed Grant's account that Mona had been the one driving his Toyota 4WD ute, despite the vehicle having a manual transmission – which her family told police she did not know how to use.
Grant, who died in 2017, was acquitted of driving-related offences relating to the incident during a 1990 criminal trial.
A further charge of indecently interfering with a corpse was dropped before the trial due to difficulties with establishing the timing of Cindy's death based on the obtained evidence.
READ MORE: CCTV captures moment stolen car crashes into fence in Victorian town
In a statement to the inquiry, Mona's mother June Smith said the family received no support during or after the criminal trial.
"The trial wasn't explained," she said.
"We didn't even know why he got acquitted. It didn't feel fair or right.
"It felt like the police were the judge, the jury and the prosecutor."
O'Sullivan accepted acute tensions existed between law enforcement and the Aboriginal community at the time and that racial bias had impacted the investigation into the girls' deaths.
"The uncomfortable truth, to my mind, is that had two white teenage girls died in the same circumstances, I cannot conceive of there being such a manifestly deficient police investigation into the circumstances of their deaths," the coroner said.
READ MORE: Government scraps plans to build Melbourne's second injecting room
She added it was clear during the initial police investigation that the girl's families were not dealt with in an appropriate or respectful manner.
Among several recommendations, O'Sullivan said police should receive training about the cultural perspectives and ongoing impact of colonisation on Aboriginal people today.
For 24/7 crisis support run by Aboriginal and Torres Strait Islander people, contact 13YARN (13 92 76).
Support is available from the National Sexual Assault, Domestic Family Violence Counselling Service at 1800RESPECT (1800 737 732).
