Police investigating the mass shooting of seven people, including four children, at a rural property in Western Australia have confirmed they believe the killer is among the dead.

The victims – three generations of the same family – were discovered in the rural village of Osmington.

They have now been officially named as Katrina Miles, her four children, aged eight to 13, and her parents, Peter and Cynda Miles.

Three firearms found at the property belonged to Mr Miles, officers have revealed.

“I wish to strongly emphasise that police do not believe any other person is involved in these crimes. Police are not searching for any other suspects,” said commissioner Chris Dawson.

He added that officers had received a phone call from a man at the property alerting them to the incident on Friday morning.

On investigation, the body of a woman was found in the house at the property, while the bodies of a woman and four children were found in a nearby converted shed where Ms Miles lived with her three sons and daughter. A seventh person was found dead outside.

It is the country’s deadliest mass shooting since a massacre in Port Arthur, Tasmania, claimed the lives of 35 people in 1996.

Relatives of the Miles family have said they are “stunned” by what has happened.

In a statement issued through the police, the unnamed family members said they were “trying to understand how this could happen”.

They continued by asking “the community refrain from speculating on the circumstances around this tragic incident”.

Osmington is a tiny rural village 20km from Margaret River, a popular tourist area.

Australia shooting: Seven people found dead near Margaret River Show all 7 1 /7 Australia shooting: Seven people found dead near Margaret River Australia shooting: Seven people found dead near Margaret River Police forensics investigate the death of seven people in a suspected murder-suicide in Osmington EPA Australia shooting: Seven people found dead near Margaret River Four children are among seven people found dead at a rural property EPA Australia shooting: Seven people found dead near Margaret River Detectives are investigating the incident, which was said to be treated as a murder-suicide EPA Australia shooting: Seven people found dead near Margaret River Two firearms were found at the scene, Western Australia Police said EPA Australia shooting: Seven people found dead near Margaret River Flowers and a note left next to a police roadblock for the victims of the incident EPA Australia shooting: Seven people found dead near Margaret River It could be the country's worst mass shooting in 22 years, police said AP Australia shooting: Seven people found dead near Margaret River Media film a property from a police roadblock where police are investigating the deaths EPA

Ms Miles, 35, and her children are reported to have moved into the property, owned by her parents Peter, 61, and Cynda, 58, three years ago.

She had homeschooled the youngsters, and was described by friends as a devoted mother.

One neighbour, Felicity Haynes, described them as “lovely people”.

“They were a very socially-aware family – doing their best to create a safe community – and that is why it is so shocking to think that could be destroyed so quickly,” she told the Australian Broadcasting Corporation.