A 24-year-old man killed his wife, three toddlers and mother-in-law at their suburban family home, where he remained for several days before turning himself in, Australian police said Monday.
The alleged murders are the third such family tragedy to rock Western Australia state in recent months.
Police charged Anthony Robert Harvey with the murders of his two-year-old twins Alice and Beatrix, his three-year-old daughter Charlotte and his 41-year-old wife Mara in the southwestern city of Perth.
Harvey, who lived in the home, is also alleged to have killed his mother-in-law Beverley Quinn, 73, after she arrived at the same address the next day.
Western Australia Police Commissioner Chris Dawson told reporters no firearms were used in the attacks which police believe were carried out with several weapons including "a blunt instrument and knives".
"We're alleging that the murders took place over two days," he said.
"The mother Mara and her three children were all murdered over a period of time on the third (of September), and that Mrs Quinn was murdered the following morning."
Dawson said the two women were allegedly attacked in the kitchen while the children were killed "in other rooms of the house".
"We are alleging that Mr Harvey remained at the... house for some days" before heading north, he added.
Police found the bodies of the five victims at the unassuming detached family home after Harvey walked into a police station in a remote mining area some 1,500 kilometres (900 miles) north of the city on Sunday -- a week after their deaths.
A Facebook profile believed to be Mara's showed her cradling a newborn in her arms, with a man reported to be Harvey beside her, and stated that she was engaged in August 2014.
A real estate listing showed a modest three-bedroom house and a standalone garage.
- 'Her girls were her world' -
Mara Harvey's sister Taryn, also Quinn's daughter and the children's aunt, wrote about her heartbreak at the killings.
"There are no words to explain the emptiness and loss that we are feeling," she wrote in a statement released by police late Monday, adding that Mara's young children "were her world" and she was "so proud of each of them".
"This world is a sadder place with the loss of these five beautiful people but Heaven has gained five new angels."
Earlier a friend of Mara's told Fairfax Media she was "pretty unlucky in love before she met him... so (when they got together) it was like 'yay, now she gets to start a family'".
A neighbour told national broadcaster ABC he had returned from a holiday to "silence in the street".
"We noticed that the house next door was pretty quiet, which was unusual," said Richard Fairbrother, who lives next door to the family's house.
"We could hear and see the kids playing in the backyard quite often."
Other neighbours spoke of a shocked community that had been close, calm and peaceful.
Dawson said it was the third tragedy involving multiple deaths in a family home in his state since May.
In July a man allegedly killed his mother and two siblings. A grandfather shot dead his wife, daughter and her four children in a murder-suicide in May.
Harvey is expected to return to court on September 19.