Son My subdistrict is divided into four hamlets, one of which is named My Lai. On March 16, 1968 USA-soldiers started a "search and destroy" mission in this area, which turned out as one of the biggest war crimes in the Vietnam war. After bombarding one of the four hamlets (Xom Lang) three platoons of Charlie Company landed by helicopter and killed almost all civilians, including women and young children. The way to kill them was throwing hand grenades into their homes and shelters, bayoneting fleeing civilians, assembling groups of civilians using machineguns to kill quickly and burn everything (houses, livestock) down. 

Although they were told by their superiors to keep their mouth shut, some soldiers went public. After hearing their stories, the public indignation all over the world led to large cover up operations within the USA army. This way the USA could condemn only one soldier, Lieutenant William Calley. He was sentenced to life imprisonment in 1971, spent three years under house arrest and was paroled in 1974 after the US supreme court refused to hear his case.