Police headquarter officials have censured a senior staff member for telling the Herald he believes an innocent man has been in jail for 20 years for a 1993 rape and murder.
Dave Henwood, an award-winning criminal profiler, last year said he had no doubt that Teina Pora was innocent of the crimes.
Malcolm Rewa was convicted of raping Susan Burdett after it was discovered it was his semen in her body but two juries could not reach a verdict on whether Rewa murdered her.
The Herald has learned Mr Henwood was officially censured for speaking to the newspaper.
He is a retired detective senior sergeant, but still works for the police in a non-sworn role.
He has won multiple awards for his work as a criminal profiler, and was accepted by the court as an expert witness in the trial which resulted in Rewa being convicted of sex attacks on 26 other women.
Rewa acted alone in all of those attacks and Mr Henwood's evidence was crucial
Last year, Mr Henwood told the Herald he was convinced that Rewa alone raped and murdered Ms Burdett. "It's one that's always stuck in the craw."
It is understood new evidence gathered to support Pora's application for the royal prerogative of mercy, under which the Governor-General can order a new trial, includes material from a British profiling expert who has come to the same conclusion as Mr Henwood.
A police national headquarters spokesman confirmed Mr Henwood was spoken to "regarding a breach of police instructions", but would not comment further because it was "an internal matter".
The spokesman said Mr Henwood was not called to give evidence in Pora's retrial "because he was not considered able to give evidence that was relevant and admissible".
Last year Mr Henwoodsaid: "They [the prosecution] were certainly not going to call me [for Pora's retrial]. The mistake was [the defence] didn't."
The reason a jury convicted Rewa of rape but not murder was that they were confused by the fact Pora had been convicted before the semen was identified as Rewa's.
"That's the only reason ... the jury can't couple that, can't understand, therefore it has to be a hung jury, two hung juries, because they can't put it together."
"I had a feeling this was all going to turn to custard somewhere down the track, and it should do because the truth has a tendency sometimes to ... come to the surface."
Rewa and Pora seemed unlikely co-offenders. Rewa was a lone wolf stalker rapist, the two men were affiliated to two different warring gangs and Rewa was 39, Pora 16.
No physical evidence was found to indicate Pora was at Ms Burdett's home.
After police posted a reward of $20,000, Pora volunteered that he knew who committed the crime. The two Mongrel Mob members he named were cleared by DNA tests and alibis.
Pora was charged despite not being able to describe Ms Burdett, find her street or point out her house.
The action against Mr Henwood has deterred other detectives who share his view from speaking publicly but one other, who also worked on the Burdett case, has written to Police Commissioner Peter Marshall.
Pora was convicted in 1994 and, when that was quashed, again in 2000. His first conviction was based on contradictory self-incriminating statements, the second on those statements and witnesses, some of whom were paid.
A world authority on false confessions, Gisli Gudjonsson, professor of forensic psychology at the Institute of Psychiatry, King's College, London, has reviewed Pora's confession and concluded it is "fundamentally flawed and unsafe".
Police have refused the Herald's Official Information Act request for details of payments to witnesses who testified against Pora.
But independent inquiries show at least three witnesses received a total of $15,000.
• Read Phil Taylor's earlier stories at http://tiny.cc/15vtsw.