John Douglas Bowie stands trial in the NSW Supreme Court for the murder of Roxlyn Bowie in 1982

As Brenda Boyd sat at the breakfast table with her younger brother, she asked their father where their mother was.

"He read me a note he said he found," she told the NSW Supreme Court jury on Thursday.

"He said she was sorry and she had to leave and he didn't know where she was".

Her father, John Douglas Bowie, 72, has pleaded not guilty to murdering her mother Roxlyn Bowie, who was 31 when she vanished from their Walgett home.

The Crown alleges the former ambulance officer killed his wife on or about June 5, 1982 so he could have an unfettered relationship with another woman.

Her body has never been found.

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Ms Boyd said she remembered the night of June 5 when her parents argued a little before her mother put her brother to bed with her help.

"I remember saying goodnight to my mother and the next morning she was not there," she said.

Her father read out a note saying it was from her mother stating she was leaving.

"I remember crying. I was eating a pie and I remember the pie coming out of my mouth."

Her father's conversation about not knowing the whereabouts of her mother and wishing he did was quite short.

"He didn't seem upset," Ms Boyd said.

After a few days, her father took her and her brother to their grandparents.

"I remember playing with my dolls and my father was packing up the house," she said.

She also remembered meeting a woman called Gail Clarke and her children, after her father told her they were going to have a new family and she would have a brother and a sister.

Earlier, the jury was read notes notes of a police interview on April 24, 1988 with Gail Clarke, who has since died.

The divorced woman said she met Bowie in his capacity as an ambulance officer in the May school holidays in 1982 when she was staying in a caravan on the banks of the Barwon River at Walgett.

She said they formed a relationship for the duration of the holidays before she returned to her Sydney home.

Some weeks later he phoned her before coming to her home towards the end of June 1982.

He told her his wife had left him and suggested he move in with her.

Ms Clarke said she refused his request, but saw him on a number of occasions before terminating the relationship after two to three weeks and never saw him again.

She said he was extremely keen to form a serious relationship but she never entertained the idea.

Ms Boyd said before her seventh birthday she, her brother and father moved into a unit with a woman called Ann whom he married.

The trial continues before Justice Dina Yehia.

Australian Associated Press

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