Celebrated former homicide detective Ron Iddles concedes a murder confession allegedly made to turncoat lawyer Nicola Gobbo was included in a 2009 statement to police.
The retired officer has backtracked on his previous staunch denial that he knew Ms Gobbo claimed Mark Perry had confessed to her about arranging the murder of self-proclaimed vampire prostitute Shane Chartres-Abbott.
Perry was acquitted by a jury in 2014.
The confession is referred to in an unsigned draft statement taken from Ms Gobbo in Bali in May 2009 by Mr Iddles and another officer, Steve Waddell.
But Mr Iddles told the royal commission into police informers on Friday that had he known about the confession, it would have changed the course of the statement-taking process.
He also said there would have been pressure to have had it signed then.
He initially claimed he had no recollection, but after his own investigations claimed it absolutely had not come up in the two days of talks with her.
Mr Iddles investigated the matter over the past year, speaking to others he expected would have known about it, and said there was no evidence anybody knew.
"Ms Gobbo is someone who wanted the glory, who wanted to tell the SDU (handlers) absolutely everything and especially in relation to this," he said.
"If there had have been a confession to her, I'm sure she would have been on the phone straight away."
But when Saul Holt QC, representing Victoria Police, presented him with a series of notes and affidavits from between July and October 2009 referring to the confession, he changed his evidence.
"Looking at all the affidavits, I must say that the confession was there. Had someone provided me this information, I would have been in a different position," he said.
"There is only one logical conclusion: it was there."
But his own barrister Robert Richter QC noted that there was still no evidence that the confession had existed prior to July 2009, leaving two months when the information could have been added.
Mr Iddles earlier accepted the only reason to include it later would be a "corrupt" reason, but made it clear he was not accusing Mr Waddell - who recalls the topic being canvassed - of wrongdoing.
"You will not find me speaking anything against Mr Waddell, ever," he said.
Mr Iddles had earlier admitted memory is fallible and it was possible that he had forgotten, but he added "it's never happened in 64 years".
Ms Gobbo also told the inquiry that she does not remember a confession from Perry or telling police that she had, and that there was no logical reason for her to have forgotten.
The confession was included in a copy of the statement sent to prosecutors, including now Justice Andrew Tinney, in July 2010.
But it was determined the statement was of no use because of Ms Gobbo's "troubled relationship" with Victoria Police.
It is not clear if Justice Tinney knew of and was referring to Ms Gobbo's informing, or the fact she had begun a civil suit against police months earlier.
Australian Associated Press