Bootlegging became a larger and more profitable enterprise when Prohibition was declared in Canada nationwide on April 1, 1918, and the Eighteenth Amendment that prohibited sale of alcohol in the United States in 1920. Through the 1920s, Perri became the leading figure in organized crime in Southern Ontario and was under constant surveillance by police. The government allowed for numerous exceptions, allowing various breweries and distilleries to remain open for the export market.
