The unit met no resistance in My Lai, which had about 700 inhabitants. Indeed, they saw no males of fighting age. They only found villagers eating breakfast.
Nevertheless, over the next three hours they killed as many as 504 Vietnamese civilians. Some were lined up in a drainage ditch before being shot. The dead civilians included fifty age 3 or younger, 69 between 4 and 7, and 27 in their 70s or 80s.
In addition, Vietnamese women were raped; other civilians were clubbed and stabbed. Some victims were mutilated with the signature "C Company" carved into the chest. One soldier would testify later, "I cut their throats, cut off their hands, cut out their tongues, scalped them. I did it. A lot of people were doing it and I just followed. I lost all sense of direction." Only one American was injured - a GI who had shot himself in the foot while clearing his pistol.
In one incident, a soldier, Robert Maples, refused an order to fire his machine gun on people in a ditch, even when his commanding officer trained his own weapon him. Hugh Thompson, a helicopter pilot had threatened to fire on the American troops in order to rescue Vietnamese women and children from the slaughter. After seeing U.S. troops advancing on a Vietnamese family, he landed his helicopter, called in gunships to rescue the civilians, and ordered his gunner to fire on any American who interfered.