Police have confirmed three licensed firearms were found at the scene of a mass murder-suicide at a rural property near Margaret River on Friday, confirming all seven members of the one family suffered gunshot wounds.

Speaking to reporters on Saturday, WA Police Commissioner Chris Dawson said he would not go into details about “motive or responsibility” but confirmed all three long arm firearms belonged to Peter Miles, the children’s grandfather.

Police confirmed that when they were at the rural farm in Osmington, about 227km southwest of Perth about 6am on Friday, they found the bodies of Peter Miles, 61, Cynda Miles, 58, Katrina Miles, 35 and her four children, Taye, a 13-year-old girl, and three boys Rylan, 12, Ayre, 10 and Kayden Cockman, 8.

Commissioner Dawson said only one person was found outside one of the buildings, one woman was located inside the main house, and five people – a woman and four children – were found inside a “converted shed”.

“I also can now confirm that police have recovered three firearms, all long arms, at the location and all three firearms are licensed to Peter Miles,” he said.

“I wish to strongly emphasise that police do not believe any other person is involved with these crimes. Police are not searching for any other suspect,” he said.

Commissioner Dawson said he would not go into details about what was said in the two-minute triple-0 call at 5.15am from an adult male, only confirming two local police officers arrived at the property about 6am.

“We know where the call was made from, we know whose phone it was made from. I have listened to the message…we believe the phone call was made from that property. I have been briefed by the homicide officers.”

“I won’t say what was said in the call. It’s far too early for me and not right that I expand on that.

“You don’t have to be at a scene to feel the horror and the sadness around such a tragic event. There are neighbours, there are friends, there are family, that are deeply affected by this.”

He said police had spoken to the children’s father and he was being given support.

“We’re providing him with as much support as we can, and he’s in a place where he’s getting…support. Police have got a very close communication with the father,” he said.

• Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14.
• Suicide Call Back Service 1300 659 467.