Labour wants a ruling overturned that's preventing serial rapist Malcolm Rewa from facing trial for the 1992 murder of Auckland woman Susan Burdett.
He was tried twice before on the charges in the late 90s, but both resulted in hung juries, prompting the solicitor general to enforce what's called a 'stay-on-prosecution'.
That means he can't be tried again -- but Labour wants that changed.
Rewa is a serial rapist who was cowering from the public two decades ago, convicted of sex attacks on 25 women.
One of his victims, Susan Burdett, was found dead in 1992. Rewa's DNA was found at the scene, and he was found guilty of her rape -- but two juries couldn't decide if he was the murderer.
Labour's justice spokeswoman Jacinda Ardern says it's time for Rewa to face a third trial.
"Why has Malcolm Rewa not been brought back to trial? Only the Crown prosecutor and police can answer that," she said.
A Newshub request saw a statement from the Solicitor-General dug up from 1998.
"Only in special circumstances will the Crown proceed with a third trial after a jury has twice disagreed on an accused's guilt of a particular charge," it read.
Labour, though, claims there are special circumstances, including the wrongful imprisonment of Teina Pora for 21 years for Ms Burdett's murder, being declared innocent and given $2.5 million in compensation.
They are also referring to a Cabinet report by retired High Court Judge Rodney Hansen QC concluding: "I find the undisputed evidence leads to the irresistible inference that Malcolm Rewa acted alone and was solely responsible for the rape and murder of Ms Burdett."
"I think it's very hard to justify why there has not been a prosecution, why he hasn't been brought to trial," Ms Ardern said.
But criminal law expert Chris Gallavin says it's not that simple.
"That's not new evidence and that would not be enough to suspend the stay and have another trial against Malcolm Rewa," he said.
The man who fought for seven years to have Teina Pora cleared wants justice served for Ms Burdett's family.
"It's really important someone with authority -- either from police or Crown Law -- fronts up and explains to the public what their position is," Tim McKinnel said.
The Solicitor-General declined a request for an interview and refused to offer any new comment in light of the latest report that points to Rewa.
He's still in jail for his rape convictions, but up for parole in two years.