Serial rapist Malcolm Rewa could stand trial for the murder of Susan Burdett for a "very rare" third time, legal experts say.
After 22 years in custody, the Privy Council yesterday upheld Teina Pora's appeal and quashed his convictions for the 1992 rape and murder of Ms Burdett.
The move has opened the possibilities for a retrial of Rewa.
In 1996, DNA from semen at the scene linked the attack to Rewa, a serial rapist with a modus operandi of offending alone.
Rewa was eventually convicted of the rape of 27 women, including Ms Burdett, but two hung juries could not reach a verdict on charges of murder.
He is currently serving a sentence of preventive detention with a 22-year minimum non-parole period for 24 rapes committed between 1987 and 1996, including 14 years to be served concurrently for Ms Burdett's rape.
PORA CASE: FROM THE VAULT
• Justice after 21 years in jail: Teina Pora 'set up for new life'
• How the Herald broke the story of Pora's innocence in 2012
• Expert says Pora confessions can't be relied on
• Police failed to check rapist Malcolm Rewa's alibi
Dean of the University of Canterbury's School of Law, Associate Professor Chris Gallavin, said there was "a good chance" that the Attorney-General, on advice of the Solicitor-General, could push for a fresh Rewa murder trial.
"They will be taking a very serious and hard look at the question of the culpability of murder for Rewa. I'd like to think they would've examined this already in some detail," he said.
"What is clear from the Privy Council's opinion is that they have recognised some striking similarities, including the DNA that places him at the scene, and the signature, or trademark, of Rewa offences and the death of Ms Burdett."
Given that the two previous juries were hung on the murder charges, it meant that new evidence would not have to be brought by the Crown.
"Hung juries are different to an acquittal, and you can just start again," he said.
But he suspected Rewa's defence counsel might challenge the move for a third trial, given the length of time that has lapsed.
Dr Gallavin said it was "very rare" to be tried three times on the one charge.
A spokeswoman for the Crown Law Office today said it was "far too early" to say whether Rewa would face a third trial.
"We are reviewing the decision in consultation with the police and family members of the victim as to the issue of a retrial. That's all we can say at this time."
Private investigator Tim McKinnel told Radio New Zealand that he believed a retrial for Rewa was a possible outcome from the Privy Council's decision.
He hinted that there was more to be told about Mr Pora's case that would come out in due time.
"There's a lot of things we want to say in time about this case ... but we really need to be so careful at the moment as we take the next step."
Mr Pora could be in line for compensation of around $2 million after his convictions for the rape and murder of Susan Burdett were quashed.
Mr Pora, 39, is today a free man after serving 21 years in prison for a crime the Privy Council found he was wrongly convicted of.
Lord Kerr said while delivering the decision that evidence from two medical experts that Mr Pora suffered from a form of fetal alcohol spectrum disorder - and in their opinion that could explain why he made what is now believed to be false confessions - was a big factor in the outcome.
The board will receive submissions on whether a retrial should be held over the next four weeks.
Stuart Grieve QC - who was commissioned by the Government to assess David Dougherty's eligibility for compensation after his acquittal in 1997 - said today that Mr Pora could be in line for around $2 million in compensation.
If a retrial is not ordered, or if Mr Pora was acquitted at a retrial, he would be eligible to apply for compensation.
Cabinet guidelines specify around $100,000 for every year spent in custody.
"He's had what a lot of people would say is the best part of his life taken from him," Mr Grieve said.
"He was only 17 when all this happened... he's missed out on an awful lot."
Mr Grieve said other factors such as loss of earnings while in prison could push the figure higher while a person's actions before imprisonment could reduce the final compensation figure.
However, compensation would only be granted if Mr Pora's case made it through "significant hurdles", Mr Grieve said.
"Assume for a moment there is no order for retrial, then Mr Pora crosses that hurdle.
"The next hurdle then is the Queen's Counsel... has to be satisfied that the claimant is innocent on the balance of probabilities."
Mr Grieve said he couldn't predict how long the process could take, but said David Bain's five-year bid for compo was a bad example.
"Certainly compensation on its own after acquittal has taken some time [in Mr Bain's case], that's for sure.
"If there was no order for retrial [of Mr Pora] then I imagine the process could begin relatively quickly."
Mr Bain is seeking compensation for more than a decade he spent in jail after being convicted of the murders of his family in 1994.
Advocate Joe Karam told NZME. News Service the process people were forced to go through in a bid for compensation was "absurdly unjust".
He said Mr Pora's successful appeal showed New Zealand's criminal justice system needed an overhaul.
"I think we need a public royal commission of inquiry into the criminal justice system in New Zealand so that we don't have these cases happening."
He said a retrial of Mr Pora would be "ridiculous from so many points of view".
Mr Bain was found not guilty at a retrial in 2009. If he is successful in his compensation bid, it is estimated that he could receive a multi-million dollar payout.
In 2001, the Government awarded David Dougherty $868,728 in compensation for the three-and-a-half years he spent in jail after being wrongly convicted of abducting and raping an 11-year-old girl.
Mr Grieve said since the compensation was made to Mr Dougherty the Cabinet guidelines had specified $100,000 per annum.
Mobile readers: Tap here to view the full document
1992, March 23: Susan Burdett raped and murdered in her home in south Auckland.
1993, March 23: Teina Pora charged with burglary, sexual violation and murder.
1994, June: Pora convicted as a party to the rape and murder on the basis of confessions he made. Sentenced to life in prison.
1996, May: Rewa arrested after attacking a young woman in the inner Auckland suburb of Remuera, DNA from Rewa's father found to match semen from Burdett crimescene.
1998: Rewa eventually convicted of the rape of 27 women, including Ms Burdett but two juries fail to reach a verdict on murder.
1998, May 30: In 1998 Rewa was convicted on multiple sex charges dating back to 1987 and sentenced to preventive detention with a minimum non-parole period of 22 years. He was convicted of the rape of Ms Burdett the following year.
1999: Court of Appeal quashed Pora's convictions as a result of the DNA evidence implicating Rewa and evidence that Rewa acted alone.
2000, June: Pora was again convicted at his retrial, based on his confessions and witnesses, some of whom it later emerged were paid. His appeal to the Court of Appeal was dismissed.
2009, September: Private investigator and former police detective Tim McKinnel visits Pora in prison and is given permission to make inquires on Pora's behalf.
2011, September: Pora team file notice of application for the Royal Prerogative of Mercy but two years later are granted an appeal to the Privy Council.
2012, May: Police's criminal profiling expert goes public in Herald with view Pora not involved; Pora's team sue police claiming it is unlawfully withholding evidence, Ms Burdett's brother says Pora is innocent.
2013, February: It is revealed police paid some prosecution witnesses.
2013, August: The Police Association call for an independent inquiry into Pora's convictions.
2014, April: Pora granted parole at his 13th appearance before the board and after spending 21 years in jail.
2014, November: Five-member Privy Council panel hears appeal.
2015, March 3: Privy Council quash convictions.
- additional reporting Phil Taylor
The victim was backing away when he was hit with a blindside punch.