At least three people, including a seven-year-old boy, were killed and dozens injured after a man drove his car into a shopping crowd in the Austrian city of Graz, a media report said.The city centre, where the incident took place, is Graz's main shopping street.An eyewitness said the car went into the crowd at a very high speed.Close to 34 people were injured in the incident on Saturday. Among those six are in a critical condition, Xinhua reported.The driver of the car is a 26-year-old man, who is suspected to have psychosis.Austrian police found no drug or alcohol in his car, but local media said the driver was accused of domestic violence in May.After going on the rampage, the man drove his car to the local police station and gave himself up to police.An Austrian official said initial investigations indicated the incident was not terror-related. The local government sent around 60 ambulances to the scene.The incident happened at around noon local time, when the mayor of Graz was riding a Vespa only metres away from the site of the accident.