No police officer involved in the bungled investigation into the death of Joshua Warneke will be sacked but two could be demoted.
The 21-year-old was walking home in Broome after a night out drinking with his friends in February 2010 when he was struck from behind with a pole by Kiwirrkurra man Gene Gibson.
But a series of police failings during Gibson's interview more than two years later, forced prosecutors to drop the murder charge against him and accept a guilty plea to manslaughter.
Police Commissioner Karl O'Callaghan revealed on Thursday that two officers were facing disciplinary action, which could ultimately end with their demotion.
"The two officers made a series of judgment calls about the ability of suspects and witnesses to understand the interview process which were wrong, and in my view, showed a lack of diligence rather than training," he told reporters.
Eight other officers have received managerial interventions while another, who should not have been involved in the investigation because of a lack of experience, remains under review.
Mr O'Callaghan said language barriers and the remote area of the attack made it a complex investigation.
But he accepted more should have been done regarding the supervision of officers, and announced a series of changes to how police handle similar cases.
It includes providing Aboriginal suspects or witnesses with an interpreter, which will require extra police funding, particularly in remote areas.
Other changes to be introduced include a special police unit to deal with witnesses and suspects from remote indigenous communities, as well as pre-recorded cautions in every Aboriginal language, similar to the Northern Territory.
The findings of the internal police review have been provided to the director of public prosecutions, who is currently considering the report.
Asked if it could lead to the case being reopened, Mr O'Callaghan said: "Any material could lead to a re-evaluation, but I'm not at liberty to reveal what's in it. The next step, if there is a next step, is in their court."
The Corruption and Crime Commission delivered its report on the case to state parliament in November, concluding that the flawed police interviews had exposed systemic failures in the force.
It called for people not proficient in English to have an interpreter and that officers interacting with Aboriginals to be properly trained in culture and language.
The WA Police Union said improvements to the homicide investigation unit was proof there were "serious deficiencies" in police resourcing, supervision and training.
Labor's police spokeswoman Michelle Roberts said the CCC report made it clear the problems went deeper than just a number of individuals.
"One of my concerns here is that we don't just see a few junior officers hung out to dry and the whole thing brushed under the carpet," she said.
"I don't think we can rely on police just patching this up themselves."
Government cuts to interpreter services last year would have a clear impact on the Aboriginal community, she added.
