The man appointed by Jiang to be President of the Opium Suppression Bureau was Du Yuesheng (nicknamed Big Ears Du) who also happened to be the leader of the Green Gang, the main criminal organisation in Shanghai. The Green Gang, which controlled the drug trade, prostitution, gambling and extortion in the city, was hired by the GMD to attack Communists and trade unionists. Du's reward for helping Jiang was to be appointed a general in the army.