Liam O'Flaherty's short story, "The Sniper," is set against the backdrop of the Irish Civil War of 1922-23. The internecine conflict split the IRA, pitting proponents of the Irish Free State, who had signed the Anglo-Irish Treaty of 1921, against the anti-Treaty Republican faction, which refused to accept any form of British dominion.
It focuses on a young Republican sniper perched on a rooftop near the O'Connell Bridge in central Dublin. After he kills a woman spotter and the machine gunner of an approaching armored car, he's badly wounded in the forearm by a bullet from a Free State sniper on the opposite roof.
In serious pain, and now with only one functional arm, the sniper realizes he needs to kill his sharpshooting counterpart just to escape with his life. By means of a ruse which involves dropping his cap and rifle from the roof to fake his death, the sniper dupes his foe into exposing himself. Using his revolver, the sniper takes careful aim, and kills his opponent. Before making his escape from the area, he can't resist a look at the face of the man he has just killed. He turns over the body and sees the face of the story's antagonist, his brother.