"Police are now responding to what I can only describe as a horrific incident".
Firearms were discovered at the scene, and the bodies appeared to have gunshot wounds.
Commissioner Dawson said police would be immediately concentrating on the actual scene itself.
He added cops acted on a tip-off after a "male person" connected to the property phoned police.
US House democrats have released ads that Russians put on Facebook
Notice, though, that none of the most popular ads are specifically political, talking about Hillary Clinton or Donald Trump. According to the committee, there were 3,393 advertisements purchased, which were seen by more than 11.4 million Americans.
Detectives from the Major Crime Squad have travelled to the town as part of the investigation, the ABC is reporting. "But I didn't have the opportunity to say hello".
Commissioner Dawson said he was unable to release further detail or specify the ages of the victims as officers were still trying to track down other family members, friends and next of kin.
A police chaplain is there to support officers.
"Regrettably, these tragedies do take their toll", Mr Dawson said.
Health Officials Declare New Ebola Outbreak In Central Africa
Tthe deadly Ebola virus made a comeback to the continent after the Democratic Republic of Congo declared its presence on Tuesday. It is spread through close contact with the bodily fluids of an infected person, including blood, vomit and diarrhea.
He said the small Osmington community would be reeling but was confident it would rally together.
Western Australia Premier Mark McGowan tweeted after the incident: "The events in our South West are tragic and shocking".
Osmington consists only of a handful of roads, farms, vineyards, holiday chalets and horse studs.
"Our thoughts and prayers go out to everyone that will be affected by this tragedy, including those first responders".
BMW recalls 300000 cars over potentially lethal fault
BMW are taking the proactive step of expanding the recall of vehicles potentially affected by the power supply issue. Following the fatality, more than 36,000 cars were recalled via the Driver and Vehicle Standards Authority (DVSA).
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