A 27-year-old woman who had been assaulted, bound and gagged, was also found while her three children in the home were unharmed.
The younger woman says they were attacked by two men in a home invasion, Superintendent Guy Buckley from Holden Hill Local Service Area told reporters on Saturday.
“The woman is alleging that there was a home invasion with two Caucasian males who left the scene in a white tradie-type four-wheel drive,” Supt Buckley said.
One of the men was wearing a white T-shirt, the other was wearing a dark hooded jumper, he said.
The younger woman’s husband was at work at the time and the older woman was his mother, Supt Buckley said.
“It’s obviously a very concerning incident,” he said. “The parties involved are very shocked and traumatised.”
The Major Crime Investigation Branch has taken charge of the investigation.
It is believed the 57-year-old woman left her Unley workplace about 6pm on Friday and drove to Valley View in a white, 2014 two-door Fiat 500 with the personalised plates MYRNA.
Police are calling for anyone who saw the car after 6pm to come forward.
Supt Buckley would not comment on whether anything was taken from the house or if the women knew their attackers.