Police are waiting to question a woman whose car plunged into a suburban Melbourne lake, killing three young children and leaving a fourth seriously injured.
The car plunged into Lake Gladman, a small waterway surrounded by parkland in a modern housing development in the city's outer west, yesterday afternoon.
Screenshot of the car submerged in a Melbourne lake. Photo: 7 News
It sparked a frantic rescue effort, as passers-by and police tried to free the woman driver and her child passengers, all aged under six.
Despite lengthy attempts to resuscitate them, one child died at the lake, a second died in an ambulance and the third died in hospital.
The surviving child is in the Royal Children's Hospital in a serious condition.
The woman is in a stable condition and under police guard in the Royal Melbourne Hospital.
The almost-submerged car remained in the lake overnight and it is expected to be towed out today, once police have collected evidence that could help explain how the incident unfolded.
"What we know at this stage ... is a car left the road slightly behind us, we don't know why and we don't know how," Superintendent Stuart Bateson told reporters at the scene.
"All we do know is that we have a very tragic set of circumstances here, and it is going to be a very harrowing investigation for everyone involved."
People left flowers and teddy bears at the lakeside, near the police cordon, which was flood-lit overnight.
The car is about 20 metres offshore, only its roof and upper portion of the windows above the water line.
All four doors are ajar, and some windows are smashed.
Witnesses have described how nearby residents jumped into the lake to pull the woman and children from the car.
Sara Omar, 17, was walking in the parklands near the lake's edge when the crash happened.
"I heard a massive 'boom'," Ms Omar told AAP of the moment the car hit the water.
She then saw a man run into the lake to try and rescue the vehicle's occupants.
"He broke the window of the back seat of the car and he tried to take the little kids out and he put them on the end of the lake," Ms Omar said.
One woman who lives opposite the lake saw firefighters pull one child from the vehicle.
"They couldn't get the car open," she told The Age.
"They were banging, trying to get the car open and trying to smash its windows."
Emergency workers tried CPR for a long time, she said.
"They looked very emotional, they were exhausted."
- AAP