Grandad "planned the mass-shooting of my four children," grieving dad of four autistic kids killed with their mum says

Last week Friday, the story of a mum, her four autistic kids, and two other adults killed in a home in Australia shocked the world (read here).

The devastated father of the four autistic children killed in a suspected murder-suicide has now accused their granddad of planning the mass shooting.

Aaron Cockman spoke for the first time yesterday after the bodies of his young children and estranged wife were f

Police discovered the bodies of Taye, 13, Ryland, 12, Ayre, 10 and Kadyn Cockman, eight, along with their mother Katrina Miles, 35, just after 6am at the rural farmhouse. The bodies of the children's grandparents, Peter Miles, 61, and Cynda, 58, were also found with gunshot wounds at the property. The tragedy is being treated as a murder-suicide and WA Police Commissioner Chris Dawson said that they are not looking for any suspect

Mr Cockman, a local carpenter and builder, said: "Peter didn’t snap. He’s thought this through. I think he’s been thinking this through for a long time. All these kids died peacefully in their beds. The (police officer) that went through, he said they looked all peaceful.

"How the hell Peter did that I still can’t figure out, but if someone did it … he did a good job, he did a really good job."

Mr Cockman had split from Katrina, which led her and the children to move in with her parents, Peter and Cynda Miles. He said he had been full of anger after Peter and Cynda Miles cut him off from seeing his children but that had "now completely gone".

"I don't feel angry," he said. "I feel tremendous sadness for my kids. I'm tremendously sad but I’ll get through this."

Cockman said police had told him the children had died peacefully, with Kaydin in his mother’s bed. Police seized three firearms from the scene on Friday, all "longarm" weapons licensed to Peter Miles. Longarm weapons are shot from the shoulder, such as rifles or shotguns and are common on farms.

Police are still investigating the circumstances leading up to the worst mass shooting in Australia since the Port Arthur Massacre in 1996