A police probe will determine if officers committed criminal acts or perverted justice in a case that saw an innocent man wrongly jailed for murder.
Alan Hall's brothers Greg, Geoff and Robert speak outside the Supreme Court. Photo: RNZ
Last month, the Supreme Court quashed Alan Hall's conviction for the murder of Arthur Easton in 1985, who was killed in a violent home invasion in 1985.
It said, and the Crown agreed, that mistakes in the case were either incompetence or a deliberate, wrongful strategy to secure a guilty verdict.
The spotlight is now turning on the police and lawyers who helped put Hall behind bars.
Police this afternoon released the terms of reference (TOR) for its two internal investigations into the case.
Read the full terms of reference for both probes here
One is a full review of the original police investigation.
The other is a more targeted probe to investigate whether officers were responsible for a decision not to include crucial witness statements about the ethnicity of the attacker in court.
The TOR notes that even under trial processes at the time, witnesses original police statements should have been disclosed to defence, and that it appears a deliberate decisions was made to omit the original descriptions of the attacker.
It also says that while practices around disclosure were "significantly" different in the 1980s, further material was also not disclosed including statements from the sons of the slain man and an ambulance driver.
Police said the reviews were being done so they could fully understand what happened before determining the next steps going forward.
The first phase of the broader review will be done by the end of September.
The Independent Police Conduct Authority and Solicitor-General are also investigating the case.
Parts of the police terms of reference which mention the SG investigation are redacted.
Two weeks ago the Solicitor-General released its terms of reference of its probe into the actions of all Crown lawyers involved in the case.
RNZ has also asked to see the IPCA's terms of reference for its investigation.
The IPCA said it does not normally prepare terms of references.
It said its jurisdiction covers police policy, practice and procedure including the actions of individual officers.