Police paid witnesses who gave critical evidence in a rape and murder case for which an apparently innocent man has been in jail for 20 years.
The police have refused a request that the Weekend Herald made under the Official Information Act for information about witness payments, but High Court files reveal that $15,000 was paid to three witnesses who testified in trials arising from the 1992 rape and murder of Susan Burdett.
Teina Pora is serving life imprisonment for those crimes.
The case became controversial after DNA testing identified semen in Mrs Burdett's body as being from Malcolm Rewa, a serial rapist who acted alone in all 24 other attacks he has been convicted of.
Last year Dave Henwood, a police criminal profiler with expert knowledge of the Burdett case, told the Herald he was convinced that Rewa acted alone and that Pora is innocent.
Private investigator Tim McKinnel said this week his inquiries indicated at least one other witness was also paid.
He described these witnesses' evidence as "critical". The former detective, with barrister Jonathan Krebs, is acting for Pora in his Royal Prerogative of Mercy application whereby the Governor-General can order a new trial.
It is not clear whether the money paid to witnesses came from a $20,000 reward which police offered at a time when they had no strong leads.
Mr McKinnel said he eventually received a document from police indicating that a payment was made to one witness. The fact that this particular witness was paid was reported in 1998 during one of four trials arising from Mrs Burdett's murder.
"Through our own investigations we have been able to establish that at least four individuals were paid rewards, and possibly as many as six or seven may have been paid, but our inquiries are being frustrated by an apparent vacuum of information on police files," he said.
It is understood that police cannot explain why their file does not appear to contain information about witness payments held by the court. The police declined to comment this week, saying it might prejudice the mercy application. The police view is that Pora, Rewa and two others were involved.
Mrs Burdett, a 32-year-old accounts clerk who lived alone, was attacked after returning to her Papatoetoe home from an evening of 10-pin bowling. She is believed to have been struck repeatedly with a softball bat which she kept in her bedroom for protection.
Pora was convicted in 1994 and, when that was quashed, again in 2000. His first conviction was based largely on his contradictory self-incriminating statements, the second on those statements and witnesses, some of whom were paid.
According to new evidence from a leading authority on false confessions, Gisli Gudjonsson, Pora lied, hoping to claim the $20,000 reward.
Dr Gudjonsson, professor of forensic psychology at the Institute of Psychiatry, King's College, London, labelled Pora's statements "fundamentally flawed and unsafe" after examining nine hours of police video interviews.
Mr McKinnel said financial gain seemed to have had "an insidious effect on the whole case".
"Eventually the confessions will be seen for what they are. And if you put them to one side, what evidence exists to support the Crown case? A large portion comes from witnesses, some of whom we now know were paid and others who may well have been paid."
No physical evidence to indicate Pora was at Mrs Burdett's home has been found. Pora was unable to take detectives to her street or point out her house unprompted. Two senior Mongrel Mob members he claimed helped to commit the crimes were cleared by alibi and DNA.
Rewa and Pora seemed unlikely co-offenders not just because Rewa was a habitual lone stalker rapist but because of their affiliation to rival gangs and their age difference; Rewa was 39, Pora 16.
A spokeswoman for the Ombudsman has said the Herald's request to review the police refusal to provide information would be investigated as soon as possible but the office is overwhelmed with 1900 cases on its books.
Herald inquiries indicate payments were made to:
• A witness granted name suppression and paid $3,000 who claimed that he had seen a young Mongrel Mob associate at Rewa's house exchanging stolen property for cannabis.
• A witness granted name suppression and paid $7,000 who claimed to have seen Pora and Rewa at a Mongrel Mob party, that gang members' bloody clothes were washed and that she had seen a 10-pin bowling trophy at a Mobster's house.
• A witness granted name suppression and paid $5,000 who claimed Pora confessed during a phone call from jail.
It is not known whether police paid a jailhouse informant who claimed he had seen Rewa and Pora together and that Pora had said he had killed before.
Read Phil Taylor's earlier stories.