Comments made at a forensic seminar gave the imputation that former prominent Perth barrister Lloyd Rayney "got away with" murdering his wife, a defamation trial has heard.
Mr Rayney is suing forensic investigator Mark Reynolds over comments allegedly made at a June 2014 forum - about two years after he was cleared of killing his estranged wife, Corryn Rayney.
Sandra Toby testified on Tuesday in the WA Supreme Court that she was furious at Dr Reynolds' interjected response to a question about a possible cold case review into Ms Rayney's murder.
In a recording played in court, he said at the event: "I was the chief supervising officer on the case and there's no need for a cold case review. The offender was identified."
Ms Toby said there were gasps among the estimated crowd of 100 people.
"It was clearly inferred that Mr Rayney was the person in his mind and I believe everyone in the room was aware of it," she said.
Ms Toby approached Dr Reynolds as he tried to leave his row of seats and he again told her: "We know who the offender is."
He allegedly added: "I would stake my kids' lives on it."
Ms Toby said he shouted that last comment in her face, but could not identify anyone around her who may have heard it.
"It felt even a little threatening," she said.
Ms Toby walked away in disgust and told her friend, forensic palynologist Lynette Milne, who said it was important and suggested she write it down, which she did.
She denied making up the line about his children, saying she clearly remembered it.
Mr Rayney said when he learnt about the comments it struck him "like a hammer".
"I was absolutely shocked. I could not believe it," he said.
"I was not the offender. I didn't kill my wife. It was patently obvious, but apparently not to Dr Reynolds."
Mr Rayney was still awaiting a phone interception trial at the time and said he was concerned a jury would be prejudiced.
"The comment was made by someone who was the relevant head of that forensic section," he said.
Dr Milne, who was also a defence witness at the murder trial, said there was a murmur through the crowd when Dr Reynolds made his initial comments.
"I understood he was saying that despite four judges finding Mr Rayney not guilty he thought Mr Rayney was guilty," she said.
Dr Reynolds admits what he said to the audience but denies it damaged Mr Rayney's reputation.
He claims to have no recollection of his conversation with Ms Toby.
In 2012, Mr Rayney was acquitted of murdering his Supreme Court registrar wife, who was found buried in a shallow grave at Kings Park.
An appeal was dismissed in 2013.
The phone interception case thrown out of court in 2015.
Mr Rayney was awarded a $2.6 million payout for being defamed by police when he was named the "prime" and "only" suspect in his estranged wife's murder in 2007.
In April, Mr Rayney was struck off as a lawyer after he was found to have secretly recorded his wife's conversations and gave false evidence about it in court.
The murder of the mother-of-two remains unsolved.