Former hospital orderly Colin Graham, 66, is charged with murdering Ms Warrick, 25, in her Ringwood home in March 1986 after taking her out for dinner.
Two men have told his Victorian Supreme Court murder trial that Graham made confessions of sorts about Ms Warrick's death and about a murder.
Craig Maddaford told the court in pre-recorded evidence played to the jury on Thursday that Graham told him he had been seeing a nurse from Ringwood.
"(He said) that they had been out for dinner or something, out on a date, gone back to her place and something happened and she died in his arms," Mr Maddaford said.
"And he remembered all the blood."
Mr Maddaford said he never spoke to Graham about the claim again and told no one until he moved back to New Zealand years later.
He learned of the cold case investigation into the death of a Ringwood nurse in 2017.
"My body went empty, everything hit the floor," he said.
He rejected suggestions from Graham's lawyer Malcolm Thomas that he made up the story in 2017.
Mr Maddaford said he hadn't told police about it in 2000 when they spoke to him about something else because Graham hadn't told him how the nurse died.
"How did I know she didn't fall of a hill or something? He didn't elaborate," he said.
He admitted contacting police about the reward for information about Ms Warrick's death but denied that's why he came forward.
"I don't care about the reward, I'm not concerned about the reward, the reward is nothing to do with it," he said.
"I'll forfeit the reward if that makes you happy, if I was successful in it - I don't care about the reward, it's just doing what's morally right. It's closure. I don't care about the reward, give it to charity."
Another man, Joseph Royle, also rejected that the reward was motivation for telling police about a 2012 alleged murder confession from Graham.
He said Graham's demeanour was "normal" when he told him in prison that he had committed a murder and not got caught yet.
Mr Royle said he "started freaking out" and crying after Graham told him.
He said he kept it to himself until 2017 when police told him a CrimeStoppers tipster said he might have information about a murder.
Graham's trial is continuing.
