MONTHS prior to her death Lainie Coldwell discovered her partner of 18 years Louis James Mahony was having an affair.
Ms Coldwell's mother Patricia Coldwell told Toowoomba Supreme Court the couple's relationship had been deteriorating in 2009 after Mahony started arguing about money.
Mrs Coldwell said she was very close to her daughter who had suddenly appeared quiet and that she knew something was wrong.
She said her daughter had gone to see a doctor and on the May Day weekend of 2009, Mrs Coldwell and her husband Trevor approached Lainie to ask what was wrong.
She said her daughter told her how she knew Mahony was having an affair.
"She said 'Mum, I've got an STD and I've never been with another man'," Mrs Coldwell told the court.
The next day Mahony had kicked Lainie out of the house for telling her parents, she said.
On August 23, 2009, Lainie Coldwell was found at the foot of a gum tree at the couple's then Charleville home.
Mahony claimed she had fallen from the tree while removing coloured lights and hit her head on the rock garden below.
The Crown has accused Mahony of killing his de-facto wife and staging the scene to look like she had fallen from the tree.
Mahony, 44, has pleaded not guilty to a charge of murder arising from the death of Ms Coldwell.
Two specialist forensic pathologists who examined the medical records and autopsy report of Ms Coldwell told the court, in their opinion, it was more likely Ms Coldwell had been struck with an object rather than having fallen from height in a tree.
Sydney-based Professor Johan Duflou and Victorian-based Dr Shelley Robertson both cited lack of any other injuries to Ms Coldwell's body as having contributed to their respective views.
Dr Robertson said had such a fall led to the head injury, she expected to see other injuries to the neck, trunk and limbs.
"I think it certainly unlikely to have occurred in that way," she said of a fall from a tree.
Both pathologists found that an antique clothes iron pictured among bloody rocks at the foot of the tree fitted the wound in Ms Coldwell's head.
Mrs Coldwell told the court she remembered that iron as being used as a door stop inside the house but never in the garden.
Among the material the pathologists observed was a 3-D model of Ms Coldwell's skull made from scans taken at autopsy.
"If you placed the front tip of the iron into the skull fracture it formed a very good fit," Prof Duflou told the court.
However, under cross examination by defence barrister Phil Hardcastle, both pathologists conceded a fall from a tree could not be ruled out completely.
"It's extremely unlikely but not impossible," Dr Robertson said.
Mrs Coldwell will continue giving evidence when the trial continues this morning before Justice James Douglas.
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