On 9 March 1988, a Winnipeg police officer shot and killed J.J. Harper, a prominent Manitoba Native leader and former executive director of the Island Lake Tribal Council. An inquest exonerated the officer of any wrongdoing, but the investigation failed to mollify Native opinion about the inadequacies and abuses of the Manitoba law enforcement and justice systems. The Harper killing stoked fires of anger and resentment still smouldering over the trial, four months earlier, of Helen Betty Osborne's murderers. The Osborne case was a startling example of the inefficiency and indifference of the police and legal systems when Natives were victims of non-Native violence. Even though the identity of her killers was widely known in the community, Osborne's brutal murder in The Pas had gone unsolved for 16 years. Official indifference impeded prosecution and damaged the evidence to a degree that, in the end, only one of the four men reputed to have been involved was convicted of the murder.
Native fury at these flagrant but not exceptional abuses prompted Manitoba's NDP government to establish an official inquiry into the experience of Manitoba Natives with the province's justice system. The commissioners, Associate Chief Justice Alvin Hamilton of the Manitoba Court of Queen's Bench in Brandon and Associate Chief Judge Murray Sinclair (himself a Native) of the provincial court in Winnipeg, travelled across the province to investigate the situation in remote as well as urban areas. Their findings called attention to a number of failings of the provincial justice system where Natives were concerned. Among the grievances listed were insensitive police officers, racist judges, lawyers who pressured Native clients to plead guilty, and the high cost of pursuing justice in the existing system. In many cases, it was cheaper for the accused in remote communities to plead guilty and pay fines, rather than travel at their own expense to the appropriate court to prove their innocence. The commissioners also observed that many Natives were imprisoned for trivial offences, because they could not afford to pay the fines that served as an alternative to a jail term.
The inquiry also devoted part of its time to investigations of the particular cases of J.J. Harper and Helen Betty Osborne. The commissioners determined that there had been a rush to exonerate the police officer who had shot Harper, asserting that the latter had been killed unnecessarily in the process of a wrongful arrest. But the inquiry's report had, beyond a pronouncement of the racism rampant in the Winnipeg police force and recommendations for procedural changes to impede a repetition of the incident, failed to offer any amelioration of the circumstances that had led to this death. In the matter of Osborne's death, the inquiry was limited to similar recommendations for change and the suggestion that additional lesser charges be laid against a second man in the Osborne case.
The commissioners concluded that it was not enough to attempt piecemeal changes to address the deficiencies highlighted by their investigations. They went so far as to recommend the development of a separate Aboriginal justice system, noting that the right to self-government supported the exercise of justice by Aboriginals according to their own laws and values. They did suggest, however, that efforts be made to hire more Aboriginals as police officers, court staff, and probation officers.
Like the Marshall Inquiry in Nova Scotia, Manitoba's Aboriginal Justice Inquiry uncovered concrete reasons for the overrepresentation of Native peoples in the criminal justice system and revealed the systemic racism of non-Aboriginal justice structures. The inquiry also emphasised the need for Aboriginal participation and input in the development of justice alternatives in order to create a workable solution.