A three-month-old baby has died after a car crash in Perth's southern suburbs, which also seriously injured two adults.
Police are investigating whether speed was a factor in the crash, which occurred on the Kwinana Freeway in Baldivis shortly before midnight on Friday night.
The three-month-old boy was taken to Princess Margaret Hospital, but died within a few hours.
The two adults who were in the car — a 20-year-old man and an 18-year-old woman — are in a serious but stable condition in hospital.
It is understood they are the baby's parents.
The car, a maroon sedan, is believed to have rolled before striking a lamp post, with the infant and both adults flung from the vehicle.
Police said a car matching the description of the one involved in the single-vehicle crash was spotted driving erratically shortly beforehand.
Anyone who witnessed the car or who has information has been urged to contact CrimeStoppers.
The crash caused authorities to close the Kwinana Freeway southbound around Safety Bay Road for more than an hour.
