A 24-year-old father has appeared in Perth Magistrates Court charged with murdering his three daughters, aged under four, as well as his wife, before killing the children's grandmother the following day.

Key points: The bodies of the women and children were found at the house after a man went to police

The bodies of the women and children were found at the house after a man went to police The man has now been charged with five counts of murder

The man has now been charged with five counts of murder It is the third apparent mass murder in WA since May

Anthony Robert Harvey allegedly killed three-and-a-half-year-old Charlotte Kate Harvey, two-year-old twins Alice Ester and Beatrix Mae Harvey, and their mother Mara Lee Harvey, 41, on Monday September 3 in their house in the northern Perth suburb of Bedford.

He is accused of murdering Ms Harvey's mother, the children's grandmother, 73-year-old Beverley Ann Quinn, in the same house the next day.

WA Police Commissioner Chris Dawson said police would allege a blunt instrument and knives were used in the crimes, but no firearms were involved.

He said the bodies of Ms Harvey and Ms Quinn were found in the kitchen of the house, with the children's bodies found in other rooms.

Anthony Harvey is accused of murdering Mara Harvey (left), the couple's three children and her mother at a house in Bedford. ( Facebook: Mara Quinn )

The five bodies were found on Sunday after Mr Harvey went to a police station in the remote Pilbara town of Pannawonica.

Commissioner Dawson said police believed he had remained in the house on Coode Street for several days after the alleged murders, before travelling to Pannawonica.

Mr Harvey was charged yesterday afternoon and appeared before Perth Magistrates Court via video link from Karratha.

Officers remain at the family home in Bedford as part of their investigation. ( ABC News: James Carmody )

Barefoot, bearded and wearing a dark grey t-shirt and jeans, he showed little emotion during the hearing and as the charges and names of his wife and children were read out to the court.

Mr Harvey replied "yes" or "I understand" when asked by the magistrate if he understood each of the charges.

He was not required to enter a plea and was remanded in custody to reappear in court on September 19.

Sorry, this video has expired Blunt instruments used by the father to kill family over days: WA police

'No words to explain the emptiness and loss'

Ms Harvey's sister Taryn released a family statement thanking everyone for their support during an "extremely dark and difficult time".

"There are no words to explain the emptiness and loss that we feeling," she said.

Beverley Quinn and her granddaughters (from left to right) Charlotte, Beatrix and Alice who were murdered in their Bedford house. ( Supplied )

"Beverley was a kind-hearted, caring mother and grandmother and was always there for her family. She was very much family-orientated and she loved her daughters and grandchildren, and would have done anything for them.

"Mara loved being a mum and she loved her girls. She was so proud of each of them and was doing a great job of raising them. Her girls were her world.

Ms Harvey is believed to have worked in the Pilbara some years ago. ( Supplied: Facebook )

"Charlotte was an energetic, bubbly, confident little girl who loved people and loved socialising. Alice was outgoing, adventurous and cheeky, while Beatrix was at times a little bit more quiet but gave the biggest hugs.

"This world is a sadder place with the loss of these five beautiful people but Heaven has gained five new angels."

Mara Harvey and Anthony Harvey ran a Jim's Mowing franchise together in Morley. ( Jim's Mowing franchises )

Ms Harvey is believed to have worked in the Pilbara some years ago, and land title records show she bought the brick-and-tile home on Coode Street back in 2008.

Neighbours said an older woman visited regularly to help with the children.

Ms Harvey more recently ran a Jim's Mowing franchise with her husband, covering Morley and surrounding suburbs north of the Perth CBD.

Mr Harvey was described on their business website as previously working fly-in, fly-out in cleaning and grounds maintenance.

Deputy Premier brands deaths 'horrible, senseless'

WA's Deputy Premier Roger Cook said it was a "senseless" event.

"Our heart goes out to the family and friends of all involved and also to the first responders who had to witness that horrible situation," he said.

"I want everyone just to hug their kids, hug their family … it's very upsetting.

The five bodies were found at the Coode Street house after a man went to a police station. ( ABC News: David Weber )

It is the third time this year that WA Police have been confronted by what appears to be a mass murder crime scene.

"Obviously we've had a series of tragic events," Mr Cook said.

"Whether there's a common cause, we are still yet to find these things out, but obviously I can understand why people are disturbed by these events.

"We will do our best to get to the bottom of the matter, to understand the issues and if there's an appropriate policy response."

Police described the suspected mass killing as a tragic event and have a man in custody. ( AAP: Richard Wainwright )

The family who lived at the Bedford house was not known to authorities, Minister for the Prevention of Family and Domestic Violence Simone McGurk said.

No hint of conflict in 'perfect family'

A neighbour, who asked for just his first name "Alfie" to be used, said he didn't know the family well, but never heard any conflict at the home.

Police say Beverley Quinn was murdered the day after her daughter and three grandchildren. ( Supplied )

"I always waved at them and the two twins were always dressed the same, beautiful little kids," he said.

"You could hear them all day there in the back, running around.

"There were never fights, arguments there, never ever."

He said Ms Quinn was always at the house helping her daughter.

Alfie witnessed police jump the fence of the property on Sunday and said he thought there had been a robbery.

"They were hammering on that back door, then others went in by the front," he said.

He said police took footage from his CCTV cameras, which were only activated at night.

Online tributes have begun pouring in for the mother-of-three, her children and their grandmother.

Ms Harvey's former classmates from Mount Lawley High School's graduating class of 1993 were shocked by the news.

Floral tributes were laid outside the house on Monday. ( ABC News: James Carmody )

"Heart broken to hear about Mara Quinn. No words. Just so very sad," Chi Hong said, using Ms Harvey's maiden name.

"That's devastating. So angry and upset," Liz Waterhouse wrote.

Ms Harvey was a member of a Facebook community group for people with twins and multiple birth babies, and the group's administrators also posted an online tribute.

"It is with a heavy heart and our deepest condolences that we are informing our community today that one of our own has been taken, in what can only be described as a shocking tragedy," the post said.

"Our thoughts and prayers go out to all those who know the family and have been touched by this tragedy."

Crime scene close to three schools

Homicide Squad and forensic officers continued to work throughout the night at the house in a bid to determine the circumstances around the killings.

A student from John Forrest Secondary College walks past the Bedford crime scene on the way to school. ( ABC News: James Carmody )

Police yesterday said the investigation was still at a "very early stage", but described the incident as a tragic event.

"It is tragic not only for the family and the friends, it is also tragic for those first responders who are forced to attend such scenes," WA Police Assistant Commissioner Paul Steel said.

"It does send a ripple through the community of Western Australia."

Sorry, this video has expired Police find five bodies at a house in Bedford

The house, on the corner of Coode St and Fort St, is less than 500 metres away from two high schools — John Forrest Secondary College and Chisolm Catholic College — as well as Hillcrest Primary School.

Students were seen walking past the crime scene on Monday morning as they made their way to school.

House had been unusually quiet: neighbour

Richard Fairbrother, who lives next door to the house where the bodies were found, said he last saw the family more than a week ago, as he had been away.

"We've just been on a holiday and come back [on Saturday] to silence in the street," he said.

Richard Fairbrother lives next door to the house where the bodies were found. ( ABC News: Marcus Alborn )

"We noticed that the house next door was pretty quiet, which was unusual, being that they had the young kids.

"We had some friends staying here who have also mentioned that they didn't see or hear anybody next door for the week that we were away."

Mr Fairbrother said he was friendly with the family and was struggling to understand how such a situation could happen.

"We'd been around to their house once or twice, and vice versa. It's just terrible to hear, terrible," he said.

"We weren't that close, [but] we could hear and see the kids playing in the backyard quite often."

Coode Street was cordoned off as police launched their homicide inquiry. ( ABC News: Eliza Laschon )

Third WA mass killing in four months

The Bedford case comes four months after seven people were found dead following a mass shooting in a house in Osmington, near the holiday town of Margaret River in WA's South West.

Katrina Miles and her four children were found shot dead in their beds, and the body of her mother Cynda Miles was found in an adjoining property with gunshot wounds.

The children's grandfather, Peter Miles, was also discovered dead from a gunshot and three firearms belonging to him were located on the property.

It was the worst mass shooting in Australia since the Port Arthur massacre in 1996, when 35 people were shot dead in Tasmania.

The Miles family (rear) Katrina Miles, Peter Miles and Cynda Miles, and children (front) Rylan, Kayden, Taye and Ayre. ( Facebook: Katrina Miles )

Then in July, a mother and two children were found dead in a house in Ellenbrook, in Perth's north.

The woman's son, Teancum Vernon Petersen-Crofts, alerted authorities to the crime after entering a nearby convenience store, where staff called police.

When officers went to the house, they found Michelle Petersen and her son, Rua, dead, and her daughter Bella in a critical condition.

She later died on the way to hospital.

Teancum Vernon Petersen-Crofts (centre) has been charged with killing three members of his family: Rua , 8 (left), Bella, 15 (top right) and his mother Michelle Petersen (bottom right). ( Supplied )

Mr Petersen-Crofts has been charged with three counts of murder and remanded to the secure wing of Graylands Hospital while he awaits his next court appearance.