Police are trying to piece together what caused a man to lose control of his 4WD, killing a four-year-old boy in a Melbourne medical centre car park.
The boy was holding his dad's hand as they left the Epworth Specialist Centre in Berwick yesterday when he was struck by the Toyota Landcruiser.
The 56-year-old driver was taken to Dandenong Hospital in a stable condition.
A witness told reporters the driver said he had just left nearby Casey Hospital after receiving dialysis treatment.
Detective Sergeant Mark Amos told reporters 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."
Police spent hours at the scene yesterday and are appealing for anyone with information to come forward.