1886    Haymarket Square Riot: A bomb is thrown at policemen trying to break up a labor rally in Chicago, Illinois, United States, killing eight and wounding 60. The police fire into the crowd.

1927    Carabineros de Chile (Chilean national police force and gendarmery) are created.

1927    Columbine Mine Massacre: Striking coal miners are allegedly attacked with machine guns by a detachment of state police dressed in civilian clothes.

1934    "Bloody Thursday" – Police open fire on striking longshoremen in San Francisco.

1974    Police in Los Angeles, California, raid the Symbionese Liberation Army's headquarters, killing six members, including Camilla Hall.

1984    A major clash between about 5,000 police and a similar number of miners takes place at Orgreave, South Yorkshire, during the 1984-1985 UK miners' strike.