Mandurah Detectives are investigating a serious crash that occurred at the Kwinana Motorplex about 12:20pm, Saturday 11 November 2017.
Eight year old Anita Board was driving a drag racing car for a test run. At the end of the run she failed to stop and struck a cement barrier.
The girl received life threatening injuries and was conveyed to Rockingham Hospital before being transferred to Princess Margaret Hospital. She died on Sunday.
Police would like to speak to anyone who was at the Motorplex who saw the crash, or has vision of the crash.
Anyone with any information is asked to call Police on 131 444 or Crime Stoppers on 1800 333 000.