The New South Wales Director of Public Prosecutions (DPP) is facing damning criticism over a 33-year-old woman's brutal death and the two suspects who have never been held to account.

Key points: Daley died from blunt force genital tract trauma in 2011

Daley died from blunt force genital tract trauma in 2011 Maris said he burnt blood-soaked mattress, underwear

Maris said he burnt blood-soaked mattress, underwear Attwater charged with manslaughter, Maris with manslaughter accessory after the fact — neither was ever prosecuted

Attwater charged with manslaughter, Maris with manslaughter accessory after the fact — neither was ever prosecuted Pressure growing on NSW DPP to overturn decision

Lynette Daley, also known as Norma, was found naked, bruised and bloodied on Ten Mile Beach in northern NSW in January 2011.

An autopsy would later find Ms Daley died from blunt force genital tract trauma.

She had suffered horrific internal and external injuries following a violent sex act being performed on her by a man who claimed to be her boyfriend, Adrian Attwater.

Ms Daley had been taken to Ten Mile Beach the previous night by Mr Attwater and his friend, Paul Maris.

Ms Daley was a mother to seven young children. Mr Attwater and Mr Maris told Ms Daley they were taking her for a camping and fishing trip.

Both men were known to police at the time.

In the back of Mr Maris's four-wheel-drive, in darkness, the two men subjected a highly intoxicated Ms Daley to a series of sex acts.

Forensic pathologists later found Ms Daley's blood alcohol concentration to be dangerously high, 0.352, in the potentially lethal range of intoxication.

Experts have told Four Corners that Ms Daley would not have been able to consent to the sex acts being performed on her that night.

Attwater, Maris charged but never prosecuted

In police videos and photos of the scene obtained by Four Corners, Mr Attwater and Mr Maris describe what they did to Ms Daley.

Adrian Attwater was charged over the death of Lynette Daley, but never prosecuted. ( Supplied )

But their version of events was found to be both inconceivable and dishonest by NSW coroner Michael Barnes following an inquest in 2014.

In the police videos, Mr Maris reveals how he set fire to and burnt key pieces of evidence including the blood-soaked mattress and Ms Daley's underwear, before paramedics or police had arrived on the scene that morning.

Following a thorough police investigation, Mr Attwater was charged with manslaughter and Mr Maris was charged with manslaughter accessory after the fact.

But neither man was ever prosecuted.

The NSW DPP formally declined to prosecute on two separate occasions, despite the urgings of the investigating police and the recommendations of the NSW coroner.

Ms Daley's family said they were deeply traumatised, shocked and confused with the NSW DPP's decisions.

They said they could not understand why the case had not been prosecuted and why both men have not been held to account over the violent death of their daughter.

"They didn't care about her," stepfather Gordon Davis said.

"She was just a statistic with the DPP and with them. You know, it was just another Indigenous girl, we'll sweep it under the carpet. You know, they're a dime a dozen, this happens all the time, we'll let it go.

The NSW DPP is under pressure to prosecute Paul Maris, who was charged over Lynette Daley's death. ( Supplied )

"I was wondering, if it would've been two Aboriginal boys had done that to a white girl, I reckon they'd be still in jail."

Ms Daley's mother Thelma Davis said she was haunted by her daughter's death.

"Just thinking about it, you wouldn't think those dirty mongrels would go that far," Ms Davis said.

"If they wanted sex, why couldn't they do it [in] a gentle way? Why did they have to be hound dogs and wild animals?"

Ms Daley's sister, Pauline, said she had also suffered both mentally and physically since the death in 2011.

"Life is empty now," Pauline said.

"We don't celebrate birthdays, Christmas anymore. Life is not the same. It's never going to be the same.

"Lynette didn't deserve to be tortured. Lynette should be still here with us, seeing her kids grow up. But we're not going to get that because they took her from us. They took a beautiful, loving, wonderful sister and a mother."

Has race played a factor?

The NSW DPP's refusal to prosecute is now drawing fierce criticism from several quarters, including legal and criminal law experts, who claim the justice system has grossly failed Ms Daley.

"I can't understand it," Associate Professor Thalia Anthony, a law lecturer and expert in criminal law at the University of Technology Sydney, said.

"I've read the findings of the coroner, the forensic reports, the autopsies, and they all seem to lead to the conclusion that there's overwhelming evidence for a prosecution of manslaughter.

"I've seen other cases with other victims with less evidence and there's been prosecutions."

The inside of the four-wheel-drive driven by Maris and Attwater ( Supplied )

Ms Anthony said Ms Daley was part of a larger pattern of Aboriginal women not being protected by the courts.

"It's not a coincidence that she is an Aboriginal woman," she said.

"They are over-represented as victims and yet do not receive the same type of support by police and by the justice system when they are victimised, and I think it's because we as a society don't treat Aboriginal women with the same dignity and humanity as we treat non-Aboriginal women or men.

"There is very strong evidence that the people involved are responsible for the victim's death."

Ms Anthony said the NSW DPP should correct the record and launch a prosecution against the people involved in Ms Daley's death.

"It would send a very important message that women, that Aboriginal women, cannot be treated in this way," she said.

"And that the offenders will not get off lightly or get off at all when they commit this type of act."

Race Discrimination Commissioner Dr Tim Soutphommasane said the coroner's findings about Ms Daley's death were "unambiguous".

"It would be deeply troubling if race featured in the DPP's deliberations about prosecuting those involved," he said.

NSW Attorney-General Gabrielle Upton issued a statement to the ABC saying the DPP was currently working on the case.

"This is a truly disturbing case, and my thoughts go to the family and friends of 'Norma'," the statement said.

"I asked the Director of Public Prosecutions to review the matter in February and that work is well underway.

"The DPP has advised me that he is carefully considering the coroner's findings and the complex legal issues raised in this case."

Pressure mounting on NSW Attorney-General

Pressure is now growing on the NSW DPP to overturn its decision not to prosecute.

"When you've got a coroner, a judicial officer, saying there is sufficient evidence, and the fact that it is in the public interest to protect vulnerable women who die as a result of a violent sexual act, there is very strong grounds for them to reconsider their decision," Associate Professor Anthony said.

"The coroner's recommendations to prosecute should be taken seriously and reviewed and that should lead to a decision by the NSW Attorney-General to have the case brought before the court."

Indigenous leaders, including Professor Marcia Langton, are also weighing in and applying pressure.

Professor Langton said she was appalled and outraged over the NSW DPP's decisions.

"This case should be taken to court," Professor Langton said.

"This case will remain in the public mind as one of those cases where justice hasn't been done. And it will gain a certain infamy because it's a denial of justice.

"I would like to see the New South Wales Attorney-General take action to ensure that this case goes to court."