The Irish Republican Army guerrillas of 1919 – 21 killed many RIC Police Intelligence officers during the Irish War of Independence . Michael Collins set up a special unit – the Squad – for this purpose , which had the effect of intimidating many policemen into resigning from the force . The Squad 's activities peaked with the killing of 14 British agents in Dublin on Bloody Sunday in 1920
Bloody Sunday
Bloody Sunday (1920)
Assassination