 He trained as a butcher after he left school, and joined the IRA's Belfast Brigade in 1975 at the age of 19, due to his identification with the Republican cause and distrust of the majority Protestant community.McGrady claimed to have participated in his first operation in July 1975, and had gone on the run in October of that same year.McGrady was held in custody from December 1975 to June 1976. for assaulting a police officer during an interrogation.