Malcolm Rewa should be the focus of a police investigation into the murder of Susan Burdett, says her brother.
Jim Burdett struggles to understand why there are no plans to put Rewa on trial for the killing for a third time, following the Privy Council decision to quash Teina Pora's convictions for rape and murder.
Rewa - who is serving a life sentence for raping Burdett and 24 other women - and Pora are the only people who have been charged with the rape and murder of the then-39-year-old.
Two juries could not decide whether Rewa was guilty of the murder, but Jim Burdett says that was because Pora - who had already been convicted of the crimes - was a "red herring".
"There is concrete merit in the police reinvestigating it with Teina Pora out of the picture.
"It focuses their investigation, because Teina Pora was a red herring, right from the start," said Burdett.
"The red herring is no longer there, it must change [the police] perspective on things."
Asked whether he meant the focus should switch to Rewa, Burdett said: "Obviously".
"We know he was there. My understanding is that's what bothered the juries about convicting Malcolm Rewa. They couldn't make sense of it. It was almost as if my sister had been raped by Malcolm Rewa, he left, then Teina Pora killed her. It's bizarre."
Police have refused to act and say fresh evidence is needed to reinvestigate any historic case.
Tim McKinnel, the former police officer who took up Pora's case more than four years ago, wants Rewa retried.
He said the fact that the Privy Council found Pora may have suffered from a miscarriage of justice was "important new evidence in the scheme of this case".
The inquiries that freed Pora had also unearthed new evidence about Rewa, said McKinnel, which would form part of any submissions made on his behalf for government compensation.
"I find it troubling that the police and Crown Law appear to have formed a view without a full and proper inquiry into all the facts."
He also pointed to the expert opinion of Dave Henwood, an award-winning police criminal profiler, whose evidence helped convict Rewa as a serial rapist.
In his opinion, Rewa acted alone in each of the rapes he committed and similarly murdered Burdett by himself.