Samuel W. Koster

Samuel William 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.
Early life.
Koster was born in West Liberty, Iowa on December 29, 1919, and graduated from West Liberty High School in 1937. He graduated from West Point in 1942, and was commissioned as a second lieutenant of Infantry.
Start of career.
After completing his Infantry Officer Basic Course, Koster was assigned to the 413th Infantry Regiment, a unit of the 104th Infantry Division. After completing organization and training at Camp Adair, Oregon, the 413th served in Europe until the end of World War II. Koster took part in four campaigns, and advanced through the positions of platoon leader, company commander, regimental staff officer, battalion executive officer, battalion commander, and regimental executive officer. During the war he also completed his Infantry Officer Advanced Course and graduated from the United States Army Command and General Staff College.
Post-World War II.
After the war Koster served with the 20th and 2d Armored Divisions at Fort Hood, Texas, including assignments as a battalion commander and division staff officer. He then served in the Intelligence staff section (G-2) at the Far East Command headquarters in Japan. After returning to the United States in 1949. he was assigned as a tactical officer at West Point.
Korean War.
During the Korean War Koster returned to Asia, serving with both Operations and Training (G-3) and G-2 staff sections of the Far East Command and the Eighth United States Army before being assigned to direct the Eighth Army's guerrilla warfare operations.
Post-Korean War.
After the war Koster completed the Armed Forces Staff College, and then was assigned to the Office of the U.S. Army G-3, where he served for three years in the Operations Directorate.
In July, 1956 Koster was assigned to Supreme Headquarters Allied Powers Europe (SHAPE) in Paris, where he served as deputy secretary and then secretary of the staff. In 1959 he returned to the United States and began attendance at the National War College, from which he graduated in 1960.
In the early 1960s Koster was assigned to Fort Benning, Georgia, where he served successively as commander of the 29th Infantry Battle Group, commander of the 1st Infantry Brigade, director of the Infantry Center and School's Command and Staff Department, and chief of staff of the Infantry Center and School.
Koster was assigned to Eighth United States Army in South Korea in 1964, serving as deputy assistant G-3 and assistant G-3. In April 1966, he was assigned as director of the Plans and Programs Division in the Office of the Army's Assistant Chief of Staff for Force Development.
By 1967 he had attained the rank of Major General, and at the height of the Vietnam War was assigned to command Task Force Oregon, later reorganized as the reactivated 23rd Infantry (Americal) Division.
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. 
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 cover up caused him to be denied this promotion, and further inquiries led the way to his demotion. He was subsequently censured in writing, stripped of a Distinguished Service Medal and demoted to brigadier general for failing to conduct an adequate investigation. Koster's appeal was turned down.
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 November 1973 with the rank of brigadier general. His decorations 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.
Death and burial.
In retirement Koster continued to reside in Maryland. He died in Annapolis on January 23, 2006. He is buried at West Point Cemetery, Sec. 18, Row G, Grave 084B.
Cultural references.
Koster is mentioned by name in the first stanza of Pete Seeger's Vietnam protest song "Last Train to Nuremberg".