The group was under the leadership of Collins. The names of those who carried out Collins' orders on the morning of 21 November 1920 were not disclosed until author Tim Pat Coogan mentioned them in his book on the history of the IRA, published in 1970. Coogan identified Lemass as taking part in the killing of a British agent as a member of the "Apostles" entourage that killed fourteen and wounded five British agents of the Cairo Gang. That day, 21 November 1920, became known as Bloody Sunday.