Key evidence in Tamihere murder trial made up

A secret witness whose testimony helped convict David Tamihere of double-murder three decades ago has been found guilty of eight charges of perjury and not guilty on one charge of perverting the course of justice of perjury on Friday.

The jailhouse informant, known only as Witness C, testified that Tamihere, while in prison, detailed sexually assaulting and killing Swedish tourists Sven Urban Hoglin, 23, and Heidi Paakkonen, 21.

The pair disappeared in April 1989 after leaving their car at the end of Tararu Stream Road in the Coromandel Ranges.

Tamihere was convicted and served 20 years behind bars but has always maintained his innocence. While he admits stealing their rental car and property, Tamihere says he never met them.

Witness C testified in 1990 that Tamihere told him the bodies were disposed at sea and that Mr Hoglin had been killed by a blow to the head with a lump of wood.

However, Mr Hoglin's remains were found in Whangamata and a pathologist says there was evidence of stab wounds to the neck and shoulder area. Ms Paakkonen's remains have never been found.

In court on Wednesday, the witness said he stood by his evidence from the high-profile trial in 1990.

"I was disgusted, I am no saint but I was disgusted," the witness said.

"I had difficulty comprehending how he could be boasting of such things."

Witness C became a police informant but six years later, he phoned Tamihere's brother John and swore an affidavit his evidence was false.

Witness C says he was forced to do that by two inmates.

"And that's when they had an iron bar and a metal blade and made threats," he said in court.

But today the jury ruled that his testimony in the trial 27 years ago was, in fact, not the truth.

Witness C's sentencing is set for October 6.