Crown lawyers say the perjured evidence of a jailhouse informant should never have been given at convicted double murderer David Tamihere’s trial, but the “irregularity” does not mean there was a miscarriage of justice.

The Crown went further, arguing the evidence against Tamihere for the killings of Swedish tourists Urban Hoglin and Heidi Paakkonen in 1989 is stronger now than it was at his trial.

Tamihere’s controversial convictions are the subject of a Court of Appeal hearing this week, after he was granted the Royal Prerogative of Mercy in 2020. The Governor-General referred the case back to the court after key evidence from a jailhouse informant was found to be false.

Those under-oath lies from Roberto Conchie Harris, who testified during Tamihere’s 1990 trial that he admitted to the killings when they shared a cell at Paremoremo Prison, is a focus of the appeal.

Harris was found guilty of eight counts of perjury in 2017. He died in 2021.

Tamihere’s lawyer yesterday told the panel of judges that Harris’ evidence, paired with evidence from two trampers who claim they saw Tamihere with a blonde woman, was a “potent recipe for miscarriage of justice”.

“Given what we know about the dangers of those two classes of evidence, that is a potent recipe for a miscarriage of justice,” James Carruthers told the court. He said Harris’ evidence was used to bolster the evidence from the trampers.

Late yesterday and today was the Crown’s turn to address the court, and lawyer Fergus Sinclair began by saying the Crown’s case is stronger now than it was in 1990, given the discovery of Hoglin’s body near Whangamatā 10 months after the trial.

David Tamihere was convicted for the 1989 murders of Swedish tourists Urban Hoglin and Heidi Paakkonen. He is appealing his convictions after being granted a Royal Prerogative of Mercy. Photo / NZME

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The discovery was controversial as the body was 70km from where the Crown focused on during the trial. But Sinclair said Tamihere had stayed near where the body was found around the same time.

He suggested Tamihere lied about his movements to keep the investigation away from the area where he allegedly dumped Hoglin’s body.

Today Crown lawyer Rebecca Thomson focused heavily on the perjured evidence of Harris, arguing the testimony wasn’t necessarily viewed by the jury as fundamental to a conviction.

She said Harris’ evidence was only a “slender strand” in the Crown’s case.

“Although it was an irregularity, it was an inconsequential one incapable of affecting the outcome,” she said. “The Crown submits the Harris evidence was a slender strand ... the force of the Crown’s case remains.”

She ran through other evidence, such as some of the tourist’s belongings that were found in Tamihere’s possession.

Swedish couple Urban Hoglin and Heidi Paakkonen were travelling the Coromandel in 1989 when they were killed by Tamihere, a 1990 jury found. Photo / Supplied

Tamihere has always admitted to stealing the tourists’ Subaru, which was “loaded with gear”.

“Only Tamihere knows why, where and how he killed [the pair], but only he can be the killer.”

The two-day hearing concluded shortly before midday. Justice Christine French reserved the court’s decision, indicating it won’t be released until at least February next year.

Tamihere, who recently turned 70, has not attended the hearing. He told NZME last week he will be at home in West Auckland mowing lawns.

Ethan Griffiths covers crime and justice stories nationwide for Open Justice. He joined NZME in 2020, previously working as a regional reporter in Whanganui and South Taranaki.