The Winter Soldier Investigation, organized by the Vietnam Veterans Against the War to publicize war crimes and atrocities by Americans and allies in Vietnam, begins in Detroit.

The "Winter Soldier Investigation" was a media event sponsored by the Vietnam Veterans Against the War (VVAW) from January 31, 1971, to February 2, 1971. It was intended to publicize war crimes and atrocities by the United States Armed Forces and their allies in the Vietnam War. The VVAW challenged the morality and conduct of the war by showing the direct relationship between military policies and war crimes in Vietnam. The three-day gathering of 109 veterans and 16 civilians took place in Detroit, Michigan. Discharged servicemen from each branch of the armed forces, as well as civilian contractors, medical personnel and academics, all gave testimony about war crimes they had committed or witnessed during the years 1963–1970.With the exception of Pacifica Radio, the event was not covered extensively outside Detroit. However, several journalists and a film crew recorded the event, and a documentary film titled Winter Soldier was released in 1972. A complete transcript was later entered into the Congressional Record by Senator Mark Hatfield, and discussed in the Fulbright Hearings in April and May 1971, convened by Senator J. William Fulbright, chair of the United States Senate Committee on Foreign Relations.