Women and children of My Lai lying by the rice field. They never knew who their enemies were and why they were killed.

Below is an excerpt from the WGBS's The American Experience article on My Lai Massacre.

On March 16, 1968 the angry and frustrated men of Charlie Company, 11th Brigade, Americal Division entered the village of My Lai. "This is what you've been waiting for -- search and destroy - and you've got it," said their superior officers. A short time later the killing began. When news of he atrocities surfaced, it sent shockwaves through the US political establishment, the military's chain of command, and an already divided American public. 

As the "search and destroy" mission unfolded it soon degenerated into the massacre of over 100 apparently unarmed civilians including women, children, and the elderly. Calley ordered his men to enter the village firing, though there had been no report of opposing fire. According to eyewitness reports offered after the event, several old men were bayoneted, praying women and children were shot in the back of the head, and at least one girl was raped, and then killed. For his part, Calley was said to have rounded up a group of the villagers, ordered them into a ditch, and mowed them down in a fury of machine gun fire. 

Word of the massacre did not reach the American public until November of 1969, when journalist Seymour Hersh published a story detailing his conversations with ex-GI and Vietnam veteran, Ron Ridenhour. Ridenhour learned of the events at My Lai from members of Charlie Company who had been there. Before speaking with Hersh, he had appealed to Congress, the White House, and the Pentagon to investigate the matter. The military investigation resulted in Calley's being charged with murder in September 1969 -- a full two months before the Hersh story hit the streets. 

As the gruesome details of the massacre reached the American public serious questions arose concerning the conduct of American soldiers in Vietnam. A military commission investigating the My Lai massacre found widespread failures of   leadership, discipline, and morale among the Army's fighting units. As the war progressed, many "career" soldiers had either been rotated out or retired. Many more had died. In their place were scores of draftees whose fitness for leadership in the field of battle was questionable at best. Military officials blamed inequities in the draft policy for the often slim talent pool from which they were forced to choose leaders. Many maintained that if the educated middle class ("the Harvards," as they were called) had joined in the fight, a man of Lt. William Calley's emotional and intellectual stature would never have been issuing orders. 

In all, 25 men were charged with murder but only Lieutenant William Calley was convicted. He was put under house arrest after serving only three days of his sentence and paroled after three years. 

Source: The American Experience and BCC.