 Numerous questions remain about the events surrounding the death of Collins because the only witnesses to his death were the members of the Free State Army convoy and the anti-Treaty ambushers.As no two stories match and participant statements from both sides are contradictory and inconsistent, unanswered questions linger about what happened that day.The man believed to have fired the fatal shot, Denis "Sonny" O'Neill, was a former officer from the Royal Irish Constabulary who served as a sniper in the British Army during the First World War, joined the IRA in 1918 and had met Collins on more than one occasion.