 On 1 February General Nguyễn Ngọc Loan , chief of the National Police , publicly executed Viet Cong officer Nguyễn Văn Lém captured in civilian clothing in front of photographer Edward T. Adams and a film cameraman . That photography , with the title of Saigon Execution won the 1969 Pulitzer Prize for Spot News Photography and it 's widely seen as a defining moment in the Vietnam War for its influence on public opinion in the United States about the war , even being called " the picture that lost the war " . 
