The Sniper (story)

The Sniper is a short story written by the Irish writer Liam O'Flaherty. Set during the early weeks of the Irish Civil War, during the Battle of Dublin, it is O'Flaherty's first published work of fiction. It published in a small London-based socialist weekly, "The New Leader" (12 January 1923) while the war that it depicted was still ongoing. The favourable notice that it generated helped to get other works by O'Flaherty published, and started his career.
The short story is widely read today in secondary schools of many English-speaking countries because it is easy to read, it is brief and it has a notable surprise ending.
Plot.
There is heavy fighting taking place in Dublin, Ireland. A Republican sniper is sitting on a rooftop eats a sandwich and drinks a bottle of whiskey. Despite knowing that it is dangerous, he decides to smoke a cigarette; instantly, a bullet hits the roof. An armored car of the Irish Free State forces arrives, and an old woman steps out of the darkness and points out the sniper's position to the soldier in the car. The sniper shoots both the woman and the man in the car. Immediately, he is hit by the enemy sniper in the right arm.
The sniper applies a dressing though he is in great pain, and 
he stays in the same position for some time. He decides to escape from the roof before morning. He is no longer able to hold his rifle and slyly tricks the enemy sniper into shooting his cap, which he places over the rifle. He lets the cap fall into the street, drops his rifle and lets his left hand hang over the edge of the roof, which gives the impression that he has been shot dead.
The enemy sniper then stands up clearly, only to be shot instantly by the Republican sniper with a revolver. The dying man falls over the roof and hits the ground. Weakened and disgusted, the protagonist moves down to the street since he is curious to find out whom he had killed.
The sniper darts across the street. A machine gun tears up the ground around him with a hail of bullets, but he escapes. He throws himself face downward beside the corpse. The machine gun stops. The sniper turns over the dead body, only to realize that the dead man is his brother.