In a car accident in Kyongju, each of the two occupants insisted that he was not driving the car. The accident was investigated to determine who the driver is through careful review of the collision report, the statements of accident and witness, photographs taken at the scene, and the expert report of the National Institute of Scientific Investigation. The accident was reconstructed based on the physical principles, injuries of occupants, damages of the involved vehicles and their final stops. A mistake was found in the expert report.