The 11th Infantry Brigade was deployed to Vietnam in December 1967 due to a need for additional American troops there, and during the Vietnam War served in the United States Army's 23rd Infantry Division (called the Americal Division). The 6th Engineer Company was inactivated on 15 January 1968, after the brigade arrived in Vietnam and reconstituted as C company, 26th Engineer Battalion, remaining in support of the 11th LIB. Elements of the brigade were responsible for the My Lai massacre where members of the brigade's 1st Battalion, 20th Infantry Regiment murdered between 340 and 500 civilians in 1968. Many of its former servicemen were interviewed in the documentary "Four Hours in My Lai". In June 1971, then Brigadier General John W. Donaldson, former commander of the Brigade would be accused and later acquitted of killing 6 Vietnamese civilians on operations between November 1968 and January 1969.