Another gruesome mass murder on the streets of north-eastern Perth.

A man's in police custody, after at least five bodies were found in a house in the suburb of Bedford.

READ MORE: Three children among those found dead at Perth home

The bodies are believed to be those of 18-month-old twin girls, their three-year-old sister, their mother, and their grandmother.

New Zealander Michelle Peterson and two of her children were found dead in similar circumstances, in a nearby suburb, in July.

Australian correspondent Steve Price told Mike Hosking this latest case is just as horrific.

"What we don't have is full detail of exactly the causes of death, although one police officer described it as the most horrific scene he's ever been involved in."

LISTEN ABOVE AS STEVE PRICE SPEAKS WITH MIKE HOSKING