ANNAPOLIS, Md. (AP) – Brig. Gen. Samuel W. Koster, who was demoted from major general after being charged in the massacre of South Vietnamese civilians at the village of My Lai, has died. He was 86.

Koster died from renal cancer at his home on Jan. 23, said his daughter Nancy Sroka.

Koster was a major general in command of the Americal Division when some of the unit’s soldiers killed hundreds of defenseless men, women and children on March 16, 1968. The Americans were not under attack, and there were no Viet Cong in My Lai.

The massacre was disclosed in 1969 by the journalist Seymour Hersh and came to symbolize the U.S. military’s moral failures in Vietnam.

Koster and 13 other officers were charged in early 1970 with trying to cover up the massacre. Koster had been in a helicopter over the area the day of the massacre and insisted he was never told a mass killing had occurred.

“I accepted those reports,” Koster testified in 1971 at the court-martial of another defendant. The general said he had been under the impression that only about 20 civilians had been “inadvertently killed.”

The Army concluded that Koster “did not show any intentional abrogation of responsibilities,” and the criminal charges against him were dismissed. But the Army found he failed to adequately investigate reports of the mass killings. He was censured, stripped of a Distinguished Service Medal and demoted one rank.

Koster called the censure “unfair and unjust” and based on “faulty conclusions,” and he spent more than a decade trying unsuccessfully to clear his name.

In a 1982 interview with The Washington Post, he said: “Getting into Vietnam in the first place was where we made a mistake.”

After leaving Vietnam, he became superintendent of the U.S. Military Academy at West Point, where cadets praised him for broadening the academy’s curriculum and for doing away with much of the hazing that plebes had to endure.

After his demotion, Koster became deputy commander of the Army’s Test and Evaluation Command at the Aberdeen Proving Ground. He retired from the Army in 1973.

Born in West Liberty, Iowa, Koster graduated from West Point in 1942. He served in Europe in World War II and directed the Eighth Army’s guerrilla warfare operations in the Korean War. He assumed command of the Americal Division in 1967. His decorations included the Silver Star, Legion of Merit and Bronze Star.

Survivors include his wife of 63 years, Cherie; three sons, all Army colonels; two daughters; 15 grandchildren; and six great-grandchildren.