In combination with these attacks, Force 136 helped initiate a countrywide uprising of the Bamar people against the Japanese. In addition to fighting the allied advance south, the Japanese were faced with heavy attacks from behind their own lines. As he advanced into Burma, Slim discovered gruesome evidence of the nature of Japanese rule in Burma, finding in village after village, Burmese peasants who had been tied to trees and bayoneted to death as the Japanese preferred bayonet practice with people rather than sandbags as normally is the case. Toward the end of the campaign, the army raced south to capture Rangoon before the start of the monsoon. It was considered necessary to capture the port because of the length of the supply lines overland from India and the impossibility of supply by air or land during the monsoon. Rangoon was eventually taken by a combined attack from the land (Slim's army), the air (parachute operations south of the city) and a seaborne invasion. Also assisting in the capture of Rangoon was the Anti-Fascist People's Freedom League led by Thakin Soe, with Aung San (the future Prime Minister of Burma and father of Aung San Suu Kyi) as one of its military commanders.