Western Australia homicide squad detectives are investigating the circumstances surrounding the death of seven people in Osmington, near Margaret River.

The slaying of seven people, including four children, in an apparent murder-suicide near Margaret River is Australia's worst mass shooting since the Port Arthur massacre in 1996.

Police were called to the property in Osmington, West Australia, about 5.15am local time, and found the bodies of three adults and four children.

It is understood police found the bodies of Katrina Miles and her children, aged eight to 13, after receiving a phone call from a "male person" about 5am local time on Friday.

FACEBOOK Katrina Miles with her four children. A mother and her four children are among the victims in a mass shooting that left seven people dead on a property in rural Western Australia in an apparent murder-suicide.

The property, a 30-acre hobby farm, is owned by Cynda and Peter Miles who bought it in late 2014, but their involvement in the tragedy has not been confirmed, WA Today reported. Katrina Miles was living with her parents.

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No one is being sought for the killings.

Cynda Miles lived at the rural property where seven people were found dead. She owned the farm with Peter Miles but their involvement in the shooting has not been confirmed.

Cynda Miles has been a stalwart in the sustainability community, volunteering with the local Transition Network and leading recycling initiatives including Cynda's Soft Salvage.

Peter Miles worked as a farmer and teacher and was formerly the manager of the Margaret River High School farm.

The Sydney Morning Herald understands their four grandchildren were schooled at the sprawling homestead, among gardens full of fruit trees and flowering natives.

JUSTIN BENSON - COOPER Police at the Osmington Road property, the scene of Australia's worst mass shooting since the Port Arthur massacre in 1996.

Members of the community said the couple were civic-minded and respected members of a "happy, wonderful" family.

POLICE DESCRIBE SITUATION AS "HORRIFIC"

WA Police Commissioner Chris Dawson would not confirm exactly how the seven died, but they were found with gunshot wounds. He said he bodies of two adults were found outside a building on the property, and five bodies were found inside. Police are yet to formally identify any of the victims.

Major Crime officers are en route to the crime scene in Osmington, near Margaret River in Western Australia.

WA Police Commissioner Chris Dawson: Police are responding to an horrific incident in Margaret River. Police were called to a rural property in Osmington and discovered the bodies of four children and three adults.



MORE: https://t.co/ykweMevBOK pic.twitter.com/Or5pgsdQlR — Sky News Australia (@SkyNewsAust) May 11, 2018

"It appears that gunshot wounds are there but I don't want to go further than that, as two firearms have been located at the scene."

He said the bodies of two adults were found outside a building on the property, and five bodies were found inside.

NICOLETTE LEFEBVRE Police at the property where an apparent mass shooting left three adults and four children dead near the Western Australia town of Margaret River.

Specialist units from Perth, including the Homicide Squad and Forensic Crime Scene Unit, have been sent to the scene.

The commissioner would not speculate on a motive but said that, at this point, police had no concerns about wider public safety.

He could not reveal any more about the identity of the people either, as police were still trying to locate next of kin, but he said police believed all seven appeared to be residents of that property.

Dawson said it was a "significant tragedy", one he could only describe as "horrific".

"This devastating tragedy will no doubt have a lasting impact on the families concerned, the communities and our staff in the south-west."

The commissioner said the police chaplain has been called to attend the scene of the tragedy to support the emergency services.

"Look, this is a horrific tragedy for any person involved, and clearly officers and other first responders attending these sorts of scenes, it is very tragic," Dawson said.

"So we have support with the police chaplain, other counsellors that will also be in attendance. We will get on with our job at, regrettably, these tragedies do take their toll on everyone."

He asked for anyone who knew anything about the incident to contact police.

The rural property in Western Australia where the shooting is believed to have occurred.

"The loss of any life is tragic, but four children and three adults, this is a significant tragedy," he said.

A COMMUNITY IN SHOCK

Margaret River Mail reporter Nikki Lefebvre said locals were "falling apart" with the news.

The shooting happened at a rural property near Margaret River in Western Australia.

Neighbour Rob Broun lives in the house across the road from the property where the shooting took place.

He said detectives came to speak to him at 9.30am today but he hadn't heard loud noises or any unusual sounds coming from the property overnight.

"There was nothing much I could tell them," said the semi-retired farmer.

NICOLETTE LEFEBVRE Police have blocked the road in Osmington.

Broun said he came down to the farm on weekends from Perth so he didn't know the residents of the property very well.

"I'd seen who I assume was the father out in a paddock one day, on a tractor. But I didn't have the opportunity to say hello."

Forensic vans, police and detectives are still arriving at the property.

Osmington is a tourist town lined by farmland and vinyards.

The local newspaper reporter said Margaret River was currently in "protection mode".

"We're banding together," she said. "That's what Margaret River does."

The president of the Shire of Augusta-Margaret River has told how the tragic deaths at a property south-west of Perth have impacted upon everyone in the area.

"It's sending shockwaves through the whole community – we're all linked in one way or another, every family," Shire President Pamela Townshend said.

Townshend described Cynda Miles as "a lovely, open-hearted, generous woman; embedded and active in the community, committed to the sustainability movement and very well known".

Townshend said a fellow councillor in a social work collective was mobilising social work connections to begin supporting people in the community in every way possible.

PICTURESQUE TOURIST TOWN

Away from the surf breaks and wineries the South West region is renowned for, the vineyards give way to paddocks full of sheep and cattle.

Winding tree-lined roads take tourists and locals through the undulating landscape to Osmington, east of Margaret River.

It is now the scene of one of the worst Australian shooting crimes in recent memory. The crime scene is so extensive, senior WA police expect to be at the site for up to five days.

"It's a crime scene and we've got to figure out what happened," the region's top cop, Superintendent Mick Sutherland told a media pack on Friday afternoon.

Several locals were allowed to drive down Osmington Road past the cordoned-off scene and to their homes and places of work.

One local who wished not to be named described the family at the centre of the tragedy as "quiet".

"They kept to themselves, although I did try to reach out to them and make contact," he said.

"This is just a quiet neck of the woods. Who would believe it?"