Detectives are trying to piece together what happened inside a Sydney home before a father shot his two teenage children dead in a "planned and premeditated" attack.
John Edwards' 15-year-old son and 13-year-old daughter were killed in a bedroom at their Hull Road home at West Pennant Hills about 5.20pm on Thursday.
About 12 hours later Mr Edwards was found dead in his own home at Normanhurst.
Police believe the 68-year-old took his own life soon after the shooting.
Acting Assistant Commissioner Brett McFadden said it was too early to say exactly what happened in the West Pennant Hills house but police believe the killings were "planned and premeditated".
John Edwards, 68. Source: AAP
They were aware of Mr Edwards over past matters but he had no recent issues with the law.
Two "quite powerful" handguns registered in the father's name sometime this year and used to kill the children, were found at the Normanhurst home, Mr McFadden added.
A number of other guns owned by Mr Edwards were also found.
Mr McFadden said the mother, who arrived at the house shortly after the shooting, was treated by paramedics for severe shock.
Flowers and tributes are seen at a property in West Pennant Hills, Sydney, Saturday, July 7, 2018. Source: AAP
Mr Edwards, described as a "recluse" by a neighbour, was a financial planner and volunteered with the NSW Rural Fire Service, Lions Club and Pennant Hills Junior AFL Club, according to his LinkedIn page.
Juliette Hackett, who lives near Mr Edwards' home, said she didn't know the family well but the teenagers "had their challenges".
"I feel very sad that John felt that there was no alternative than the horrific thing he did," she told AAP.
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