An investigator says it was obvious Gail Maney didn't murder Auckland man Deane Fuller-Sandys in 1989.

Maney and Steven Stone's murder convictions have been quashed, and a re-trial's been ordered for Stone.

Colin Maney and Mark Henriksen have also had their accessory to murder convictions quashed.

The Crown's accepting the police failed to disclose important information, which caused a miscarriage of justice.

Private Investigator Tim McKinnel told Heather du Plessis-Allan that work is underway towards gaining compensation.

He says it became clear the Crown case was an absurdity, and those who looked at the case knew fairly quickly there'd been a miscarriage.

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