Four former colleagues of John Bowie have told a Sydney court about separate occasions he said "pigs don't leave any evidence".
The 72-year-old is facing a murder trial after pleading not guilty to killing his wife Roxlyn 40 years ago.
Ms Bowie's body has never been found.
Mr Bowie was an ambulance officer in Walgett when his wife disappeared on June 5, 1982.
The court heard that six days later, he requested a transfer to Bankstown Ambulance Station in Sydney's west and left Walgett on June 25 that year.
The prosecution has alleged Mr Bowie was involved with a piggery near Walgett, but Mr Bowie's barrister told the court that association ended before Ms Bowie disappeared.
"It's uncontradicted he had nothing to do with the piggery at that time and no one sees him anywhere near the piggery (when Mrs Bowie disappeared)," defence barrister Winston Terracini SC told the court.
Pigs 'don't leave anything'
Witness Gabrielle O'Dea said she heard a remark while working at Bankstown ambulance station with Mr Bowie in 1986.
She told the court she was alone with Mr Bowie in a lunch room and there'd been no prior conversation.
She told the court Mr Bowie said "if you ever want to get rid of anybody, feed them to wild pigs. They don’t leave anything, not even bones".
"I paused and said 'that's disgusting'," Ms O'Dea told the court.
"There was no further conversation, I got up and left the room."
Mr Terracini told Ms O'Dea "I suggest your memory is faulty about that".
"My memory is not faulty, sir," she replied.
Former colleague 'amazed' by comment
The court heard the second instance happened when former ambulance officer Edward Taylor worked with Mr Bowie at Tregear Ambulance Station in Sydney's west.
He told the court Mr Bowie said "police are giving me a hard time about my wife but the pigs do a good job and don’t leave anything behind".
"I didn't reply, I was a bit amazed someone would say something like that," Mr Taylor told the court.
"He just walked off."
Mr Taylor told the court the conversation took place at some point between 1986 and 1989, while they were alone in the meal room.
Witness George Keane told the court Mr Bowie was involved in a conversation at Tregear station about murders, but couldn't place exactly when; saying it could have been 1987 or 1988.
Mr Keane said he was with three ambulance officers, including Mr Bowie, in the meal room when the topic was raised because "I think someone had watched a movie about it".
"If you murder someone how do you get rid of the body, that was the question," he said.
He said one ambulance officer, possibly him, brought up using lime, another ambulance officer suggested acid and another said cremation.
"Between the group the consensus was bones would still be left," he told the court.
He said Mr Bowie "piped up" that "pigs don’t leave anything not even meat or bones".
Mr Keane said Mr Bowie was asked "wild pigs or domestic?" and Mr Bowie said "domestic".
Mr Terracini put to the witness that he'd suggested the use of lime to dispose of a corpse but "obviously sir, you're not involved with committing murder", with which Mr Keane agreed.
'They'll never find her'
The court heard witness Desmond Scotcher was Bankstown Ambulance Station's senior officer when Mr Bowie started working there.
Mr Scotcher told the court detectives arrived at the station and asked to speak with Mr Bowie on a day in 1982.
He said later that day he entered the meal room and Mr Bowie was there.
He said he and Mr Bowie remained alone together for the next 30-40 minutes.
"The first thing he said when I entered the meal room was 'do you want to know what the police were here for' or words to that effect," Mr Scotcher said.
He told the court he declined.
"Nothing more was said until when I was leaving the meal room ... he came up with the statement 'pigs don’t leave any evidence'," he said.
Mr Scotcher said Mr Bowie told him "they will never find her'" while they were in the plant room of Bankstown station, but he didn't know whether it was the same day or another day.
During cross examination, Mr Terracini suggested the witness hadn't remembered the conversation well.
"I disagree," Mr Scotcher replied.
The trial continues.
