William L. Calley, Jr., a U.S. Army officer convicted of murder in connection with the deaths of several hundred unarmed residents in a small, rural village during the Vietnam War, has died at the age of 80.

Calley died on April 28 at a residential end-of-life facility in the southern city of Gainesville, Florida. His death was reported by The New York Times and Washington Post based on information from public records.

Calley was a young junior lieutenant when in March 1968 he led a small platoon into My Lai 4, a hamlet located along the central coast of what was then South Vietnam. He had orders to find and kill members of the Viet Cong, the military arm of North Vietnam that often carried out surprise attacks on U.S. and South Vietnamese forces.

Despite finding no Viet Cong soldiers, the platoon went on a killing spree, shooting several hundred women, children and elderly men. Some women and young girls were gang raped and shot, while the soldiers either shot or stabbed infants and children using the fixed spears on their rifles before burning down the village.

The incident was not revealed publicly in the U.S. for more than a year before information provided by other soldiers led the Army to charge Calley and other personnel involved in the massacre, including at least one general who was charged with covering up the incident.

Calley was court-martialed and convicted of murder in 1971 and was initially sentenced to life in prison. He only spent a few days in jail before President Richard Nixon ordered him to be transferred to house arrest. His sentence was eventually reduced to 10 years in prison before he was freed on bail and granted parole in 1974.

The U.S. military says 347 villagers were killed that day, while Vietnam estimates the death toll at 504. Calley was the only person convicted in the My Lai massacre, with other defendants either acquitted or their charges dropped before facing court-martial.

Calley spent several years living in anonymity in the southern state of Georgia working at a jewelry store operated by his father-in-law. After years of silence, he expressed remorse about his role in the My Lai massacre during an appearance before a local civic group in 2009.

“There is not a day that goes by that I do not feel remorse for what happened that day in My Lai,” Calley told the audience. “I feel remorse for the Vietnamese who were killed, for their families, for the American soldiers involved and their families. I am very sorry.”