Barbara McCulkin and her daughters Vicki and Leanne. The family disappeared in 1974.
Barbara McCulkin and her daughters Vicki and Leanne. The family disappeared in 1974. Contributed

'I killed the McCulkins. They'll never find the bodies'

"I KILLED the McCulkins. They'll never find the bodies."

This is the confession Vincent O'Dempsey allegedly made to a man he was growing marijuana with in the 1990s.

Warren McDonald told a Brisbane Supreme Court jury on Thursday that the 78-year-old Warwick resident made the confession while they were discussing security issues surrounding their illegal enterprise at Carrara.

Mr O'Dempsey has pleaded not guilty to three charges of murder and one of deprivation of liberty over the disappearance of Barbara, Vicki, 13, and 11-year-old Leanne McCulkin who were last seen at their Dorchester St, Highgate Hill, home on January 16, 1974.

Mr McDonald, who told the court he had a criminal record, said Mr O'Dempsey would say "loose lips sink ships" when talking about "security" surrounding the drug crop.

Mr McDonald said Mr O'Dempsey was concerned about their drug pickers and others involved in the marijuana crop leaking information about the business.

Mr McDonald said he was responsible for keeping the crop secure.

Mr McDonald said he used to drive Mr O'Dempsey to and from the plantation and it was during a trip to Warwick that Mr O'Dempsey allegedly revealed he had "several notches on his belt".

"He said 'Security has got to be tight'," the witness said. "We don't want people leaving the crop.

"He (Mr O'Dempsey said 'You need a notch on your gun. When I was your age I had several notches on my gun, you need a kill'."

Mr McDonald said that was when the topic of the McCulkins came up.

"He said he killed the McCulkins and Shorty was nothing but a rapist," Mr McDonald said.

"He said they'll never catch me because they'll never find the bodies."

Mr McDonald said he would never forget the conversation and that Mr O'Dempsey told him to "never repeat it".

"He said: 'If you want to live a long and healthy life, never repeat a word that will get you in trouble'," Mr McDonald said.

"I never repeated it."

Another witness told the court that Ms McCulkin's husband Robert William 'Billy' McCulkin was "terribly upset" when he found out his estranged wife Barbara and their two daughters were missing.

Estelle Long, who married Mr McCulkin in 1977 and divorced him eight years later, told the jury he had no "unexplained absences" around the time his family went missing.

Ms Long described to the jury the night Mr McCulkin told her his family was missing.

"He pulled me aside and said 'Barb and the kids are missing'," she said.

"He was terribly upset and worried.

"I thought that they'd probably ran away, but it turned out they hadn't.

"He was extremely worried and upset."

Ms Long and another witness, Ellen Gilbert, told the court Mr McCulkin was violent towards women.

Ms Long said she saw Mr McCulkin, who is deceased, slap his sister in the face days after the McCulkins disappeared.

Ms Gilbert, who worked with Ms McCulkin in a milk bar, said her colleague came to work with bruises and other injuries.

Ms Gilbert said Ms McCulkin told her the injuries were caused by Mr McCulkin.

The Crown alleges Mr O'Dempsey and Gary Reginald 'Shorty' Dubois murdered Mrs McCulkin and her daughters because they feared Ms McCulkin could link them to a nightclub fire in 1973.

Mr O'Dempsey's trial was separated from the trial of Mr Dubois.

The trial before Justice Peter Applegarth continues.    - ARM NEWSDESK