The elite ex-officer division proved to be much more effective than the Black and Tans especially in the key area of gathering intelligence . Auxiliary companies were intended as mobile striking and raiding forces , and they scored some notable successes against the IRA . On 20 November , the night before Bloody Sunday , they captured Dick McKee and Peadar Clancy , the commandant and vice-commandant of the IRA 's Dublin Brigade , and murdered them in Dublin Castle . That same night , they caught William Pilkington , commandant of the Sligo IRA , in a separate raid . A month later , in December , they caught Ernie O'Malley completely by surprise in County Kilkenny : the IRA officer was reading in his room when a Temporary Cadet opened the door and walked in ; " He was as unexpected as death , " said O'Malley . In his memoirs , the commandant of the Clare IRA , Michael Brennan , describes how the Auxiliaries nearly captured him three nights in a row
Bloody Sunday
Bloody Sunday (1920)
Auxiliary Division