Police say a man accused of deliberately crashing a car into pedestrians outside Melbourne's Flinders Street train station, sending 19 people to hospital and creating peak-hour chaos, has a history of assault, drug use and mental health issues.
Police said the driver was a 32-year-old Australian citizen of Afghan descent, and was known to police, but was not on bail at the time of the incident.
Of the 19 admitted to hospital, 15 are in a stable condition — including a four-year-old boy and the driver — and four are in a critical condition.
Acting Chief Commissioner Shane Patton said the man was arrested by an "heroic" off-duty police officer.
"To step in when you see that trauma, not understanding what the threat is … and take somebody into custody not knowing what he is risking himself — it is heroic," he said.
But he said there was no evidence to indicate there was a connection with terrorism.