Official Army photographer Ron Haeberle traveled with Charlie Company into My Lai on March 16, 1968. The Company was told that dozens of Viet Cong troops were passing through the area, retreating from battle after the Tet Offensive. Captain Ernest Medina had told his men that all Vietnamese remaining in My Lai after their arrival would be Viet Cong members or sympathizers.

Following the massacre, during which between 347 and 504 civilians were killed, the story remained largely out of the public eye until the media published Haeberle's photographs in November 1969. These photographs would became key evidence in the Army's five-month investigation led by General William R. Peers.

The following gallery showcases a selection of Ron Haeberle's images from the My Lai Massacre as they were used in the Peers investigation.

Many of the images are violent and graphic in nature.