JEDDAH, 12 February — A Civil Defense officer in the southern city of Khamis Mushayt was stabbed to death by a group of youngsters following a quarrel, Al-Riyadh newspaper reported yesterday. The 40-year-old officer was taken to Surat Obaidah Hospital, where he succumbed to his injuries. The incident occurred when the officer, who was off duty, intervened as a group of young Saudis tampered with goods at a shop. Police arrested the murderer, a 17-year-old, within one hour of the crime.