The Perth family found dead in their home have been named

New details have just emerged about the mum, grandmother and three daughters who were found dead in their home in Perth.

Detectives found the bodies of Mara Harvey, 47, her daughter Charlotte, 3, two-year-old twin girls Alice and Beatrix, and her mother Beverley Quinn, 74, in their home in Bedford, Perth, on Sunday.

Mara, who owned the house, in the city's north-east, was married to Anthony Harvey and he was 18 years her junior.

The couple lived together in the house, and she gave birth to daughter Charlotte a year after Mr Harvey proposed in 2014. Both of them worked for a Sino Steel Pilbara mine.

The family was described as quiet and happy by neighbours who said the kids would often play in the backyard and greet their dad when he came home from work.

Kimberly Shackelton said, ‘'They were just a normal, everyday family,' she said.

'You'd think with something like this there would be warning signs but they were so quiet and seemed happy.

'You'd never see them fight or shout at each other, just those lovely kids playing and running around the front yelling "daddy" as he left for work.

'Those poor kids, they never got to have a life.'  

A man in his 20s is in custody but has not been charged.

Rebecca Della, who lives next door with her partner Richard, told Daily Mail Australia she felt they were a model family.

'Even the week before they seemed happy and cheerful, I never heard them have any fights,' she said. 

'They were quiet except for their kids always playing in the backyard, we never expected anything was wrong.' 

‘They were a lovely family,’ said a neighbour who did not want to be named. ‘Nothing to suggest that this could or would ever happen.’