The brother of Arthur Allan Thomas says the Independent Police Conduct Authority is gutless for deciding notto investigate his complaint complaint against the police commissioner.
Des Thomas told the authority the police delayed investigating alleged criminal conduct by detective Bruce Hutton, who was terminally ill.
But the authority said there was no new evidence which could lead to a prosecution and Mr Thomas took too long in filing his complaint.
Des Thomas says its reasoning is flawed, becausehis evidence is new information and the delay in him filing his complaint is the fault of the police.
Des Thomas complained about the role of a detective, Bruce Hutton, who was found to have planted evidence that led to the wrongful conviction of Arthur Allan Thomas for 1970 murders of Harvey and Jeanette Crewe.
Des Thomas complained to the police commissioner, Peter Marshall, in 2012, alleging criminal conduct by Bruce Hutton.
Mr Marshall referred the complaint to a police review of the case that was already underway.
But Mr Thomas claimed the police delayed the investigation because they knew Mr Hutton was terminally ill - and he asked the IPCA to investigate.
The IPCA says there is no new evidence to suggest there could be a successful criminal prosecution of any police officer in relation to the case.