"He didn't seem enthusiastic if you know what I mean?"
McGowan defended Australia's strict firearm laws but said he would wait and see if the coroner had any suggestions for legislative change.
The property, close to Margaret River, south of Perth, is owned by Cynda and Peter Miles, whose daughter Katrina, has 4 autistic youngsters believed to be home-schooled.
The others are believed to be their 35-year-old daughter Katrina Miles and her four children - daughter Taye, 13, and sons Rylan, 12, Arye, 10, and Kadyn Cockman, eight.
Dawson refused to be drawn on who the person was that alerted police, their relationship to the victims or whether they heard gunshots.
Mr Cockman was estranged from the late Ms Miles.
Police have not confirmed who dialed triple-zero but the two-minute recording is likely to provide some answers surrounding the horrific loss of life.
But there are other indications: police vehicles blocking roads; and the community center in nearby Margaret River offering counseling with television news cameras clustering outside.
Their grandfather Peter Miles, 61, was found with what police are investigating as a self-inflicted gunshot wound.
Australia's gun laws are widely acclaimed as a success, with supporters including former U.S. president Barack Obama saying Australia has not had a single mass shooting since they were implemented.More news: Mars Helicopter to Fly on NASA's Next Red Planet Rover Mission
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On Saturday locals said fingers pointing at the grandfather of the family "do not make sense", with some alleging media reports and investigators had "got it wrong".
"We are stunned and still trying to understand how this could happen", they said.
The family members asked community members to not speculate on the circumstances of the deaths, according to the Australian Broadcasting Corp.
Overwhelmingly, we are asking ourselves how to set up measures to ensure other farming families in crisis in regional Australia receive real assistance before another tragedy occurs.
The extended family is fully co-operating with police, while the children's father is also getting the support he needs. "If it wasn't for him, I wouldn't have Katrina, I wouldn't have her kids", Aaron Cockman told reporters, speaking publicly for the first time since the tragedy.
Police said they went to the scene after receiving a call from a man connected to the property at 5:15am, but did not give further details.
On Friday, officers found one adult dead outside a building on the property, which lies 20 kilometres north-east of the town of Margaret River.
Osmington resident Meg Janes told the same newspaper that she knew the family affected, saying: "We'd swap plants and seedlings from time to time".
Mr Dawson said police were "some way" from completing their investigation and the examination of the crime scene would still take several days.