Twenty years after a landmark Royal Commission inquiry into black deaths in custody, once-optimistic observers could be forgiven for concluding that little had changed.

If the plight of Australia's indigenous people continues to be the wound on the nation's soul, Doomadgee's home - Palm Island - is a microcosm of that sore.

Situated 65km off Queensland's northeast coast, it is a place of majestic natural beauty. Yet the conditions for those who live there rival the worst on the planet.

Unemployment runs at 90 per cent, many residents can't read, write or speak English, and an average of 17 people 'live' in each of the largely derelict houses. Their life expectancy is 50 - about 30 years lower than that of the average Australian.

Palm Island is plagued by alcoholism, drug abuse and domestic violence. In one eight-month period in 2004, there were 16 youth suicides and eight domestic murders - all this in a community numbering no more than 4,000.

The foundation for Palm's dysfunctional future was put in place almost a century ago when authorities earmarked it as a penal settlement for 1,600 so-called 'problem cases' and 'uncontrollables' from throughout Queensland. For decades, residents were subjected to brutal and poverty-stricken conditions as wages and other funds were 'managed' and misappropriated by authorities.

Health suffered and, in the 1960s, the death rate among children under four was 13 times higher than their white counterparts, with most dying from malnutrition-related diseases. A decade later, 75 per cent of child outpatients were still diagnosed as severely underweight. When control of the island was finally passed to the community council in 1985 it merely prompted the immediate dismantling of houses, shops, farming equipment and a timber mill, which were shipped on barges back to the mainland.

A 2006 report commissioned by state premier Peter Beattie after Doomadgee's death blamed his government and its predecessors for the island's problems. The report, compiled by lawyer Scott McDougall, also outlined the need for the establishment of 'functional policing'.

That was clearly absent in November 2004, when Doomadgee was arrested and taken to the police watch house. He was dead just 45 minutes later.

Last September, Queensland's deputy coroner, Christine Clements, ruled that one of the island's officers, Sergeant Chris Hurley, was responsible for the death.

There had been a scuffle between the pair after Sergeant Hurley arrested an inebriated Doomadgee for swearing. Sergeant Hurley claimed the fatal injuries were caused when they both fell on a concrete step, but witnesses testified that the officer hit the 36-year-old several times in the abdomen. An autopsy revealed Doomadgee's liver was almost split in two and he suffered four broken ribs, a ruptured portal vein, a haemorrhaging pancreas and a black eye.

'The consensus of expert medical opinion was that a simple fall through the doorway, even in an uncontrolled and accelerated fashion, was unlikely to have caused the injuries,' Ms Clements wrote in her 40-page report. 'I find that Sergeant Hurley hit Mulrunji while he was on the floor a number of times. I conclude that his actions caused the fatal injuries.'

Cases like Doomadgee's, and widespread suspicion over how the deaths occurred, prompted the establishment of the 1987 Royal Commission. After four years, the A$40 million (HK$244 million) inquiry found that Aboriginal deaths in custody were in proportion to their overall representation in the prison population.

The real problem was that Aborigines, who comprised less than 2 per cent of Australia's population, accounted for 15 per cent of its inmates. Although the commission recommended that arrest and imprisonment should be a last resort, that rate has since risen to 22 per cent.

Criminologist David Biles, who was the commission's head of research, disagrees with politicians, who argue that offenders must be put behind bars.

Mr Biles points to wildly differing rates of imprisonment around the country - inmate numbers in the Northern Territory are almost three times higher per capita than in New South Wales - saying that states with more inmates can't claim to be safer.

Other critics accuse Australia's federal and state governments of adopting only the simplest of the commission's 339 recommendations and ignoring tougher measures aimed at tackling the root cause of Aboriginal disadvantage. Mr Biles believes far more needs to be done to improve health, housing, education and employment opportunities.

Doomadgee's case has also strengthened widespread suspicion that police are above the law, with a riot in Australia's far northeast last week underscoring the tension between police and residents in many remote Aboriginal communities.

Up to 300 people went on the rampage in the Cape York town of Aurukun following allegations that Aboriginal man Warren Bell had been assaulted in custody. Six officers, family members and Aboriginal elders barricaded themselves inside the station during the trouble. As police internal affairs began an inquiry into Mr Bell's detention, 15 alleged rioters were charged.

And it's not just remote areas that suffer. In 2004, Sydney's Redfern district - home to much of Sydney's Aboriginal community - witnessed violent riots following the death of a 17-year-old boy from injuries sustained when he was impaled on a metal fence as he fell from his bicycle. Family and friends said it was the result of a police chase. Forty officers were injured by rocks and petrol bombs in the riots that followed, and a railway station set ablaze.

Back on Palm Island, there have been revelations that the investigating officers were friends of Sergeant Hurley, dining at his house on the night of the death. They failed to mention the assault allegations in their report to the pathologist conducting the first autopsy.

On the first morning of the inquest, Queensland Police Commissioner Bob Atkinson praised Sergeant Hurley as a 'very fine officer', and at its conclusion, Police Union president Gary Wilkinson described the coroner's findings as 'rubbish'.

Then, last month, the state's director of public prosecutions, Leanne Clare, announced there was insufficient evidence to proceed with charges against Sergeant Hurley, who continues to work on 'desk duties'. Despite the coronial findings, she said Doomadgee's death had been the result of a 'complicated fall' and a 'tragic, tragic accident'. Her decision sparked controversy and protests nationwide. When the state government bowed to public pressure for an independent review of the evidence, it chose a retired judge who had been on the selection panel that appointed Ms Clare.

Last week, the judge stepped down and was replaced by former New South Wales chief justice Sir Laurence Street, who said he came without 'personal baggage'.

His appraisal, due next month, has the potential to calm the tinderbox atmosphere on Palm Island. But solutions to its deeper troubles will be no closer.