Police have confirmed that the family of four who were found deceased in a house on Sydney’s North Shore were poisoned with gas.

The gas was released from multiple bottles that were found throughout the house.

A police source told the Daily Telegraph ‘’There was a lot of pre-planning that went into this."

None of the bodies have shown any signs of violence and each family member was in a different section of the house

The family has been named as mother Maria Lutz (43), father Fernando Manrique (44), daughter Elisa Lutz (11) and son Martin Lutz (10) - were found, along with the family dog, after police broke into their home in Davidson yesterday. 

Both of the children were deaf and living with non-verbal autism.

Police entered the house at around 11:20am yesterday after a family friend raised concerns for the family’s welfare when Maria hadn’t shown up for a shift at the school’s tuckshop.

Family neighbour Sonja Perry told the newspaper that mother Maria had struggled with her children saying ‘’Maria used to tell me how hard it was on her and her husband having two kids who were deaf and dumb''

“She said it was a heavy thing on her heart and some days she found it impossible to cope.”

Police are now searching for where the family could have purchased the gas bottles from. They are not looking for anyone else in connection with the deaths.

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