A couple found dead in a Melbourne home had suffered "serious trauma" injuries, but three young children were left unharmed in another room.
A 44-year-old Meadow Heights man found sitting in the driveway of the Moonee Ponds home with non-life threatening injuries is helping police with the investigation.
The children are now with other family members.
"The fact that we've got three young children aged five and below and they've been in a house where such a horrific incident has occurred is tragic," Homicide Squad Detective Senior Sergeant Shane O'Connell said.
Police were called to the Darling Street property just before 11.30pm (AEDT) on Sunday.
Det O'Connell said it was too early to speculate on the motive for the murders, nor did he know of the relationship between the 44-year-old Meadow Heights man and the couple.
No weapons have been found yet, but the crime scene is still being processed.
"I have no information that would suggest that firearms are involved," Det O'Connell told reporters on Monday morning.
"The victims sustained serious trauma injuries and the full extent of those injuries will be determined by post-mortem examination.
"It's apparent they had been murdered."
The post-mortem examinations will be conducted on Monday.
A tradesman's van parked in the street was taken away by police.
"A vehicle has been removed from the vicinity of the scene and we have some information that links that vehicle to this crime and that will be forensically examined to determine the extent, if any, of its involvement in this," Det O'Connell told Fairfax Radio.
He said it appeared the couple had been in bed, but their bodies were found in the main part of the house.
Police believed the children had slept through the attack, he said.
