Lawyer Stewart Levitt, who is acting on behalf of Ms Dhu's family in a human rights complaint with the Human Rights Commission, has told NITV News he considers the treatment Ms Dhu suffered to be akin to what would have taken place in a Nazi concentration camp.
The complaint lodged last week with the commission is seeking remedies for institutional racism and sexism.
Yamatji woman Ms Dhu died in custody in 2014 after being detained for unpaid fines at the South Headland Police Station in WA's Pilbara region.
A coronial inquest found she suffered catastrophic deterioration in her health during the three days, with the coroner describing the treatment of Ms Dhu as 'inhumane'.
But in the some of the strongest language around the case to date, Mr Levitt has told NITV News "it was more than inhumane" it was "deplorable neglect bordering on commandant treatment as in a concentration camp".
"The people that suffered from disease were just left to die and rot in the concentration camps and that is exactly what happened to Ms Dhu."
He said the CCTV vision of how she was treated over the three days in custody in South Hedland brings to mind the shocking images from World War II.
"I mean the sort of films that you see of people suffering from typhus in Aushwitz," he said.
"It was criminally culpable in my respectful submission... and charges should be laid if appropriate."
Mr Levitt also acted for the Palm Island class action claimants in the landmark case that found police's response to the 2004 riots was racist, with the community awarded $30 million.
He is confident the complaint with the Human Rights Commission will be successful, but he says more needs to be done to prevent the mistreatment of Aboriginal and Torres Strait Islander people in police custody.
"We have to bring a human rights complaint because it’s the only way we can ventilate these concerns that we have - that time and time again Indigenous people are victims of appalling mistreatment and the perpetrators are never brought to justice," he said.
"Where’s the evidence that there’d been malpractice suits against their health workers. Where's the evidence that there's been any consideration given to charging the police with negligence manslaughter?"
Mr Levitt says there needs to be independent investigations in such cases, and suggests that these be undertaken by an out-of-state police force.
"I don't think that the state governments... should be responsible for overseeing the investigation of what their own police forces or health services are doing and that responsibility should be transferred to the federal government or to other state governments."
Ms Dhu was 22 when she died. Her grieving family is still fighting for justice.
"They're not coping very well particularly... and it's understandable because it's not just the loss of a child but it's the state standing behind those people who were responsible for taking a child away from you in circumstances where there was the most deplorable neglect,” Mr Levitt said.