Curbs on jailhouse witnesses urged

the Crown to try to show that Pora and Rewa knew each other in order to argue that they had acted together.

In his report, Justice Hansen said the possibility that Rewa had acted alone seemed to have been ruled out.

At the retrial, the prison witness claimed to have seen Rewa and Pora together. He had not, however, mentioned Rewa as an associate of Pora’s before Rewa was arrested.

Hansen found the process by which the prison witness identified a photo of Rewa to be suspect and noted that a senior officer on the case had given him “a personal loan of $150 and a supportive letter to the court when he was sentenced on domestic violence offending”.

Tim McKinnel, a former police detective who worked for several years to expose the Pora miscarriage of justice, finds the police’s reliance on prison witnesses to be “troubling”. “It is difficult to see why the police couldn’t see that for themselves. There were plenty of red flags. The favourable treatment he got from police, including a senior officer on the Burdett inquiry lending him his own money, raises some pretty important questions.

“It is difficult to know what weight the jury put on his evidence, but he gave critical evidence in Pora’s retrial — evidence that didn’t exist at the first trial.” The prison witness has since died in a road accident. Do the police have a conflict of interest? Prisoners are well placed to hear confessions from other inmates. They may also be motivated to lie.

Canterbury University sociology professor Greg Newbold has practical experience to go with academic interest, having served time in prison as a young man for drug offending.

He knew several informants during that time, including the two put before the Thomas Commission.

“Both got days out of jail,” Newbold said. “One was hoping for early parole. He wasn’t a pathological liar, he was just mercenary.”

The police told the Herald that they will investigate any reported perjury offence, irrespective of whether the witness appeared for the defence or prosecution.

“Police have an interest in encouraging witnesses to come forward and be prepared to give evidence in court, as long as this evidence is the truth,” said national crime manager Detective Superintendent Tim Anderson.

The police have no data about their use of prison witnesses because they do not collect it, but Anderson was not aware of their ever having charged such a witness for perjury.

However, while Harris’ sentencing judge did not find any cases of the police having charged a Crown prison witness, Justice Christian Whata did cite four examples where the police had charged witnesses for “perjury to procure acquittal”.

Strong influences work against the police charging a prosecution prison witness for perjury, said Newbold.

“They will never do it because they don’t want to discourage their witnesses from coming forward . . . They don’t want to be seen to be stamping on the toes of people they are hoping will assist them.

“I think sometimes they suspect themselves their evidence isn’t very