Three people remain hospitalized in critical condition after a car plowed through pedestrians on Thursday in Melbourne, Australia. Photo by Joe Castro/EPA-EFE

Dec. 22 (UPI) -- Three people remained hospitalized in critical condition Friday, a day after a car struck 19 people in Melbourne's central business district.

The driver of the vehicle was arrested by an off-duty police officer at the scene Thursday. The vehicle drove onto train tracks and through an intersection crowded with pedestrians before a concrete base stopped its progress.


Those critically injured include two South Koreans, one a 4-year-old boy, with head injuries and an Australian man. Others in the hospital are a Venezuelan man, an Irish woman, an Indian man and a Chinese man. Four Australians, including the police officer who made the arrest, are also hospitalized.

Police said the driver is a former Afghan refugee who arrived in Australia in 2004, and that he has a history of drug abuse and mental illness and was charged with assault in 2010.

Terrorism is not believed to be a motive for the incident, officials said.

A second man, who used a cellphone to record the incident, was also arrested at the scene Thursday. The second arrest prompted speculation that he and the driver may have been working together. Police said they found three long knives and marijuana in a bag he carried.

"He was taken into custody to determine whether he was, in fact, connected with the incident," Acting Chief Commissioner Shane Patton said.

After determining that the driver of the car acted alone, the second man was released but will be charged with marijuana possession and possession of a controlled weapon.