Ernest L. Medina, an Army officer whose troops were responsible for the mass killing of hundreds of unarmed Vietnamese civilians in March 1968, died on May 8 in Peshtigo, Wisconsin, at age 81. As commander of C Company, 1st Battalion, 20th Infantry Regiment, 11th Infantry Brigade, 23rd Infantry Division (Americal), Medina was sent on a mission to pursue Viet Cong reportedly operating around My Lai. Instead, his company found unarmed civilians, who were rounded up and killed. Later court-martialed and charged with involuntary manslaughter of more than 100 civilians, Medina testified in 1971 that he never saw nor ordered “any slaughter,” but helicopter pilot Hugh Thompson Jr., whose intervention saved some of the civilians, and Lawrence Colburn, riding with Thompson, witnessed Medina shoot and kill an unarmed wounded Vietnamese girl…