The following day the Italian king, Victor Emmanuel III, dismissed Mussolini, remarking, At this moment you are the most hated man in Italy. Mussolini was immediately arrested and imprisoned. The Italian population rejoiced.
But by April 1945, with the Allies advancing north through Italy, Mussolini knew the end was in sight. Together with his mistress, Clara Petacci, and a few followers, Mussolini fled and headed for the Swiss border. Stopped by Italian partisans on April 26, Mussolinis attempts to disguise himself with a Luftwaffe overcoat and helmet had failed.
On April 28, 1945, at the picturesque Lake Como, the partisans stopped the car; pushed Mussolini and Petacci out, and ordered them against a wall. Whilst the partisans pronounced the death sentence, Petacci flung her arms around Mussolini and screamed, No, he mustnt die. Petacci was shot and fell. Mussolini ripped open his jacket and screamed, Shoot me in the chest! The executioner, a communist partisan by the name of Walter Audisio, did so. Mussolini fell but was not dead. Another bullet in the chest ensured that he was. The bodies were heaped into the back of a van, together with those of Mussolinis last followers, and transported to Milan.
In the city their bodies were delivered to the Piazzale Loreto, the scene of a mass execution of partisans the year before. The corpses were beaten and urinated upon and finally left to hang upside down, for public display, from a rusty beam outside a petrol station.
http://www.historyinanhour.com/2010/04/28/mussolini-execution/