Investigative Journalist Seymour Hersh Breaks My Lai Massacre and Cover-Up to an Outraged American Public

The first reports claimed that "128 Viet Cong and 22 civilians" were killed in the village during a "fierce fire fight". General William C. Westmoreland, MACV commander, congratulated the unit on the "outstanding job". As related at the time by the Army's Stars and Stripes magazine, "U.S. infantrymen had killed 128 Communists in a bloody day-long battle."

Initial investigations of the My Lai operation were undertaken by the 11th Light Infantry Brigade's commanding officer, Colonel Henderson, under orders from the Americal Division's executive officer, Brigadier General George H. Young. Henderson interviewed several soldiers involved in the incident, then issued a written report in late April claiming that some 20 civilians were inadvertently killed during the operation. The army at this time was still describing the events at My Lai as a military victory that had resulted in the deaths of 128 enemy combatants.

Six months later, Tom Glen, a 21-year-old soldier of the 11th Light Infantry Brigade, wrote a letter to General Creighton Abrams, the new overall commander of U.S. forces in Vietnam, accusing the Americal Division (and other entire units of the U.S. military) of routine and pervasive brutality against Vietnamese civilians. The letter was detailed and its contents echoed complaints received from other soldiers.

Colin Powell, then a 31-year-old Army Major, was charged with investigating the letter, which did not specifically reference My Lai (Glen had limited knowledge of the events there). In his report Powell wrote: "In direct refutation of this portrayal is the fact that relations between American soldiers and the Vietnamese people are excellent." Powell's handling of the assignment was later characterized by some observers as "whitewashing" the atrocities of My Lai. In May 2004, Powell, then United States Secretary of State, told CNN's Larry King, "I mean, I was in a unit that was responsible for My Lai. I got there after My Lai happened. So, in war, these sorts of horrible things happen every now and again, but they are still to be deplored."

The carnage at My Lai might have gone unknown to history if not for another soldier, Ron Ridenhour, a former member of Charlie Company, who, independently of Glen, sent a letter detailing the events at My Lai to President Richard M. Nixon, the Pentagon, the State Department, the Joint Chiefs of Staff, and numerous members of Congress. The copies of this letter were sent in March 1969, a full year after the event. Most recipients of Ridenhour's letter ignored it, with the notable exception of Congressman Morris Udall (D-Arizona). Ridenhour learned about the events at My Lai secondhand, by talking to members of Charlie Company while he was still enlisted.

Eventually, Calley was charged with several counts of premeditated murder in September 1969, and 25 other officers and enlisted men were later charged with related crimes. It was another two months before the American public learned about the massacre and trials.

Independent investigative journalist Seymour Hersh, after extensive conversations with Calley, broke the My Lai story on November 12, 1969; on November 20, Time, Life and Newsweek magazines all covered the story, and CBS televised an interview with Paul Meadlo. The Cleveland Plain Dealer published explicit photographs of dead villagers killed at My Lai.

In November 1969, General William R. Peers was appointed to conduct a thorough investigation into the My Lai incident and its subsequent cover-up. Peers' final report, published in March 1970, was highly critical of top officers for participation in a cover-up and the Charlie Company officers for their actions at My Lai 4. According to Peers's findings:

[The 1st Battalion] members had killed at least 175–200 Vietnamese men, women, and children. The evidence indicates that only 3 or 4 were confirmed as Viet Cong although there were undoubtedly several unarmed VC (men, women, and children) among them and many more active supporters and sympathizers. One man from the company was reported as wounded from the accidental discharge of his weapon.

However, critics of the Peers Commission pointed out that it sought to place the real blame on four officers who were already dead, foremost among them being the CO of TF Barker, LTC Frank Barker, who was killed in a mid air collision on June 13, 1968.

Lieutenant William Calley was convicted of murder for his role in the March 1968 My Lai massacre, which left hundreds of Vietnamese civilians dead. Calley ordered the men of Charlie Company, 1st Battalion, Americal Division to shoot everyone in the village. He himself rounded up a group of villagers, ordered them into a ditch, and then mowed them down with machine gun fire. Sentenced to life in prison, Calley was seen as a scapegoat for the Army's failure to instill morale and discipline in its troops. Upon appeal, his sentence was reduced. He was eventually released from prison in 1974. He later found work in the insurance business.