The bodies of Miles, his wife Cynda, daughter Katrina and four grandchildren were found in Osmington on Friday.
The three generations had moved in 2015 to Osmington, a village of fewer than 700 people near the tourist town of Margaret River, to grow fruit, media reported.
"This is a strong, connected community and I know that we'll all support each other and we'll get through this together", she said.
The victims were the mother, Katrina Miles, and her four children, along with Katrina's parents, Cynda and Peter Miles.
Mr Dawson confirmed the firearms were licensed to Mr Miles. The elder Ms Miles has a side business in making woollen goods.
Grandfather Peter Miles, 61, is suspected of murdering his entire family before turning the gun on himself in Osmington, east of the Margaret River in WA on Friday. "I know that my officers here who I have spoken to are dealing with a very tragic scene".
Mr Dawson described the discovery as "devastating". The other five, a woman and the children, were found in a converted shed structure, Dawson said.
Police were attempting to make contact with the victims' relatives, Dawson said.
"We are devastated by this shocking event", the statement said.
Richard Dossor said he had spoken to the farm maintenance worker about looking after his property while he was away.
Aaron Cockman’s four children were killed in a suspected murder suicide carried out by their grandfather at home. Pic EPA REBECCA LE MAY
"It's not fair. It's not fair", she told 9 News Australia, explaining that she heard three gunshots, followed by two more, at about 4 a.m. Friday but did not think much about it. Police initially said that two people were found outside.
Cockman, who told reporters in Margaret River he was estranged from Katrina, said "Peter didn't snap".
"It's surreal that this is happening here in our attractive little community".
"It just shows violence is throughout a society, we're not immune down here". Proud locals say people go there to retire or bask in a rural paradise.
West Australian Premier Mark McGowan has met with grieving residents of the Margaret River community.
"We are treating this as a matter in which clearly six persons are the subject of a homicide crime scene".
Police do not believe that there is a "larger threat to public safety", perhaps suggesting that the shooter was one of the people found dead.
The commissioner said the incident had taken its toll on first responders.
"In a land of only 18 million people, almost everyone knew someone, or knew someone who knew someone, who was among the 500 or so people in the small waterfront historic site at Port Arthur that day", Sullivan wrote.
Police rushed to the rural property just after 5am after receiving an emergency call.