New details have emerged about the horror car crash that killed a 4-year-old boy.

The father of a four-year-old boy who was struck and killed by an out of control four-wheel-drive in Melbourne on Friday told witnesses he blamed himself for the accident.

Sarah and Cameron Smith, who were travelling behind the Toyota Land Cruiser outside the Epworth Specialist Centre in Berwick when tragedy struck, told the media the boy’s father said it was his fault as they fought in vain to save his life.

“I remember the dad saying ‘it’s my fault’. It’s not his fault,” witness Sarah Smith told the press congregating outside the accident.

As police try to piece together exactly what happened on Friday afternoon, AP report the 56-year-old driver of the vehicle had just left nearby Casey Hospital after receiving dialysis treatment.

Witnesses at the scene said the driver’s speed was increasing before impact, with one telling reporters the four-wheel-drive became airborne for about “six or seven metres” and took out at least 10 vehicles.

Detective Sergeant Mark Amos told AP on Friday the father and son, from Narre Warren South, had just walked out of the clinic when the boy was hit.

“The father’s gone out with his son, holding his hand, doing what good dads do,” he said.

“There’s just no way you could’ve predicted this could happen.”

Detective Sergeant Amos added that staff working at the Epworth medical centre also tried to save the boy’s life, and “couldn’t have done anymore than they did”.

“They were straight into CPR, attempting to revive and resuscitate this young man.”

The driver was taken to Dandenong hospital in a stable condition, while another woman in her 60s who was also struck is recovering at Casey Hospital.