A man who bludgeoned his mother and her partner to death was obsessed with a Guns N' Roses song about genocide, a Hobart court has heard.
Nicholau Francisco Soares, 29, has pleaded not guilty to murdering academics Delys Weston and Gavin Mooney, at their rural property south of Hobart in December 2012.
Soares used a hammer and a blockbuster to attack the heads of the couple while they ate dinner.
His lawyer Rochelle Mainwaring has told a Tasmanian Supreme Court he was insane at the time of the killing.
The court heard Soares was obsessed with the Guns N' Roses song Civil War and its reference to genocide.
A note quoting the song's lyrics was found in the house where the couple were killed, his brother Alex Soares told the court.
"He would play a 10, 20-second segment of the song ... for hours on end, laughing, giggling," he said.
Mr Soares said his brother had suffered a serious mental illness and had been committed for treatment several times in Western Australia in the years before the killing.
Soares experienced delusions, including the belief his parents and mental health workers were trying to kill him, he said.
He had also tried to join the army to learn skills he believed he would need to survive an impending apocalypse.
"This was his world, this was his reality ... 24/7 believing he was going to die," Mr Soares said.
The court was played two triple-zero calls made by Soares on the night he killed the couple, and again 24 hours later.
Identifying himself only as "Fred", he told an operator he'd killed two people with a hammer.
"I've got two dead bodies here," Soares said.
"I've killed two people."
Soares had moved to the Tasmanian property in the weeks before the killings to live with his mother and Professor Mooney.
The court heard the couple had been unable to quickly arrange the medication Soares needed when he became unwell in their home.
Prof Mooney and Dr Weston had moved from WA to Mountain River, 30 kilometres from Hobart, about a year before their deaths.
Internationally renowned Prof Mooney had been head of Health Economics and Director of the Social and Public Health Economics Research Group at Western Australia's Curtin University from 2000 until his retirement in 2008.
He held honorary and visiting positions at the Universities of Sydney and NSW, the Menzies Research Institute in Hobart and in South Africa and Denmark.
Dr Weston, who had completed a PhD on the political economy of global warming, held university positions in South Africa and Tasmania.
Share
