In July 1934 , police in San Francisco were involved in several encounters with striking longshore workers . After two picketers were killed , the other area unions joined together and called a general strike of all workers ( the " Big Strike " ) . Subsequent criticism of the police was probably the occasion for the coining of the term " police riot . " During the Vietnam War , anti-war demonstrators frequently clashed with police , who were equipped with billy clubs and tear gas . The demonstrators claimed that the attacks were unprovoked ; the authorities claimed the demonstrators were rioting . The most notorious of these assaults , which was shown on television and which included national television reporters in the chaos , took place during the August 1968 Democratic National Convention in Chicago , which was the scene of significant anti-war street protests . The actions of the police were later described as a police riot by the '' Walker Report '' to the US National Commission on the Causes and Prevention of Violence
1968 Democratic National Convention
1968 Democratic National Convention
Police riot