At least four person were killed and four injured in a severe collision between two cargo trailers on National Highway Excise check post near Nawabshsh here on Wednesday. According to the police a trailer was being checked on Sakrand excise check post when suddenly another trailer hit it, resulting in death of four persons who were identified as Saraj Khan, Muhammad Qasim, Khalid Pervez, and Muhammad Ismail while four were injured. The injured have been shifted to the People Medical hospital Nawabshah, where their condition is said to be out of danger, doctors said. The Sakrand police are investigating the accident.