The internal police review of the Crewe murders is nearly finished, two years after it was begun.
A spokesman for police national headquarters said the review of the original investigation of the murders of Harvey and Jeannette Crewe would be completed in "the next few months".
The review was announced by then Deputy Commissioner Rob Pope in October 2010 after Rochelle Crewe spoke publicly in the Herald for the first time, asking for the police to reinvestigate the deaths of her parents in 1970.
The police refused to reinvestigate - despite the murders remaining unsolved since Arthur Allan Thomas received a royal pardon in 1979 - but agreed to re-examine the original investigation, which was tainted by corruption.
Ms Crewe was initially told the inquiry would take a "matter of months".
That turned into years because of the complexity of the case, including the analysis of 100,000 pages of documents.
The police spokesman did not say if the review would be made public. He appealed for anyone with information on the murders in Pukekawa, south of Auckland, to come forward.
Ms Crewe told the Herald she was looking forward to when the review was completed. Information had been drip-fed to the public over the past 42 years and "twisted to fit different theories, [which] has caused further harm to my family and is a further injustice", she said.
"I am hoping this review will put a stop to this and I am able to satisfy myself that everything that could have been done to find my parents' murderer has been done."By Jared Savage @jaredsavageNZH Email Jared