The Los Angeles County coroner's office is investigating the deaths of twin sisters as possible suicides after their bodies were found in a Hawaiian Gardens home with that of their 87-year-old mother, who appears to have died of natural causes.

Coroner's assistant chief Ed Winter said Tuesday autopsies on the elderly woman and her 58-year-old daughters are pending.

He says the twins' deaths were believed to be possible suicides, and the mother's death the result of natural causes.

The three were found Monday in a house where a car had been left running in the garage.

A relative checking on the family's welfare discovered the older woman's body in a bedroom.

Her daughters' bodies were found on the floor of the home's detached garage, where the car's motor was running.