McGuinness acknowledged that he was a former IRA member , but stated that he left the IRA in 1974 . He originally joined the Official IRA , unaware of the split at the December 1969 Army Convention , switching to the Provisional IRA soon after . By the start of 1972 , at the age of 21 , he was second-in-command of the IRA in Derry , a position he held at the time of Bloody Sunday , when 14 civil rights protesters were killed in the city by soldiers of the 1st Battalion , Parachute Regiment
Bloody Sunday
Bloody Sunday (1972)
Martin McGuinness