At least four people were killed while six others were injured in a roadside accident on GT Road near Kamra area of Attock on Wednesday morning, police said. According to details, the mishap occurred owing to excessive speed, as a wagon collided into a trailer trying to overtake it near Kamra on GT Road, killing four people and injuring six others. After the incident, the bodies and the injured have been shifted to nearby hospitals. Police registered case and started investigation.