Samuel W . Koster Samuel W . Koster ( December 29 , 1919 – January 23 , 2006 ) was the highest - ranking United States Army officer punished in connection with the My Lai Massacre . Koster was slated for promotion to the rank of Lieutenant General ( three star ) at the time he was charged , but was demoted and ended his military career in mild disgrace . Born in West Liberty , Iowa , Koster graduated from West Point in 1942 . He was a regimental executive officer in Europe during World War II , and directed the Eighth Army ' s guerrilla warfare operations during the Korean War . Koster attained the rank of Major General , and was placed in command of the Americal Division in Vietnam in 1967 . My Lai Massacre . On March 16 , 1968 , a company of Americal Division troops led by Captain Ernest Medina and Lieutenant William Calley slaughtered hundreds of civilians in a South Vietnamese hamlet known as My Lai ( referred to as " Pinkville " by the troops ) . While no official count was made , soldiers and investigators later estimated that 350 to 500 women , children and old men were killed with grenades , rifles , bayonets , and machine guns ; some were burned to death in their huts . Corpses were piled in ditches that became mass graves . No Viet Cong were ever discovered in the village and no shots were fired in opposition . To many Americans at home , the massacre marked the moral nadir of the war in Southeast Asia and became a pivotal event in the conflict . Koster was not on the ground at My Lai , but he did fly over the village in a helicopter while the soldiers moved in , and afterward . He later testified that he believed only about 20 civilians had died , although he also said that he was told about " wild shooting " and about a confrontation between ground troops and a helicopter pilot ( later identified as Hugh Thompson ) who tried to stop the killing of civilians . Koster later ordered subordinates to file reports on the incident , but they were incomplete , and one was even lost . Worse , these reports were never sent to headquarters , as military protocol required , until an Americal veteran named Ron Ridenhour triggered a secret high - level investigation with a three - page letter he sent to the Pentagon , the president , and members of Congress in March 1969 . Freelance investigative journalist Seymour Hersh broke the story of the massacre to the wider public in November 1969 . Early in 1970 , Koster and 13 other officers were charged with trying to cover up the massacre . Charges were dropped , however , after the Army determined that he " did not show any intentional abrogation of responsibilities " . Koster , who was the Superintendent of the United States Military Academy at West Point at the time , was due to be promoted to the rank of Lieutenant General ( three - stars ) , but his involvement in the My Lai coverup caused him to be denied this promotion , and further inquiries led the way to his demotion . He was subsequently censured , stripped of a Distinguished Service Medal and demoted one rank , to Brigadier General , for failing to conduct an adequate investigation . Later life . Following his demotion , Koster was reassigned to become deputy commander of Maryland ' s Aberdeen Proving Ground , in charge of Army weapons testing . He retired from the military in 1973 . His decorations included the Silver Star , the Bronze Star Medal , and the Legion of Merit . His sons are career Army officers , two having graduated from West Point . After his retirement , Koster worked for 12 years as an executive vice president for the power transmission division of Koppers and Hanson Industries in Baltimore , overseeing power plants in the United States and Canada . Cultural references . Koster is mentioned by name in the first stanza of Pete Seeger ' s Vietnam protest song " Last Train to Nuremberg " . " " Do I see Lieutenant Calley ? Do I see Captain Medina ? Do I see Gen ' ral Koster and all his crew ? " "