An affidavit from Witness C, claiming that he fabricated evidence during David Tamihere's double-murder trial, was written because he could no longer live with his testimony, a court has heard.
The man, whose identity is suppressed, is accused of perjury and attempting to pervert the course of justice after he testified that Tamihere told him in prison that he'd killed Swedish tourists Urban Hoglin and Heidi Paakkonen and dumped their bodies at sea.
The alleged false testimony came at Tamihere's murder trial about 27 years ago, but Witness C's name and identifying details have been suppressed since.
On August 25, 1995, Witness C swore an affidavit stating that he lied and gave false evidence in the High Court trial.
However, he retracted it the following year.
Tamihere's brother, former Labour Cabinet Minister John Tamihere, had helped prepare the affidavit for Witness C, after three phone calls from the jailhouse informant. He was this morning cross-examined by Witness C's lawyer Adam Simperingham over the legal document.
"If a secret witness rings you, and you put yourself in my shoes, I'm very much involved in this case - he's [David Tamihere] my brother," John Tamihere said.
"You've got to test the bona fides of this bloke [Witness C].
"I took notes, he affirmed it."
John Tamihere said he initially questioned whether Witness C was on the "road to Damascus" or had "an epiphany".
"This case is all about that isn't it? It's about the credibility of cellmate confessions," he said.
However, John Tamihere said he concluded that Witness C could no longer live with his false testimony, which led to a man being found guilty of two murders.
John Tamihere also said a 1996 interview between the late Sir Paul Holmes and Witness C also "meets with a number of things in the affidavit".
The affidavit was also released to the press by John Tamihere to "shake the tree".
He said the motivation behind releasing the document was to encourage any previously unheard witnesses to come forward and to test the evidence of the two other secret witnesses.
"If one [secret witness] recants and the other corroborates that, then you've got an even more compelling case," John Tamihere said.
The affidavit reads, in part, that Witness C no longer wished to be associated with the evidence he gave during Tamihere's trial.
"What happens, Mr Simperingham, if the other two secret witnesses recant, on the back of some courage [from Witness C]?
"As with Arthur Allan Thomas and as with others there are other options ... you have to demonstrate that there has been a miscarriage of justice."
John Tamihere said he had "no idea" Witness C was "going to come out of the woodwork", but that the affidavit claimed his evidence at trial was "induced, trained, coached and taught".
David Tamihere was convicted of the murders and eventually released from prison in 2010 after serving 20 years. He has always professed his innocence.
Hoglin's remains were discovered by pig hunters in 1991 in bush near Whangamata, about 70km from where the murders were alleged to have taken place.
Paakkonen's remains have never been found.
Witness C has pleaded not guilty to eight counts of perjury and one of attempting to pervert the course of justice.
The case was laid as a private prosecution by Witness C's long-time fellow prison inmate and serial litigator Arthur Taylor, and will be led by lawyer Murray Gibson.
Witness C was one of three jailhouse informants who gave evidence for the Crown during Tamihere's trial.
Tamihere admitted stealing the Swedes' car but denied having met them.