Police in western Kentucky say an employee shot and killed four people at a plastics plant early this morning, before killing himself.Officers say the shooting happened after an employee at Atlantis Plastics had an argument with his supervisor. The man apparently went home on break and returned with a gun.In addition to the four deaths, police say two others who were injured were flown to hospitals in Evansville, Indiana. The names of the victims and the shooter have not been released.