The Prohibition was enacted by the ratification of the 18th amendment in 1919 and went into effect a year later.
The Prohibition caused an intense rise in demand for alcohol, bringing forth the rise of organized crime running bootlegging businesses, especially bring to being the rise of Al Capone.
Al Capone was the most notorious gangster during the time of the prohibition always followed by the press, often painted by the media as a Robin Hood type of hero.
Scarface, as he was called for the deep scars on his cheek, was estimated to make nearly 100 million dollars per year from his gambling, bootlegging, and prostitution ring.
A Group of Federal Law enforcement officers led by Elliot Ness tasked with taking down Al Capone.
Ness hand picked his team, based on skill as well as character, and in their deeds they became legendary for being fearless in their raids against Capone's bootlegging business and for being incorruptible, giving them the name of untouchable.
But, in the end Capone wasn't taken down in a raid. No, a 44 year old accountant by the name of Frank J. Wilson put him behind bars, not for murder, or smuggling, or other numerous crimes, but for income tax evasion. The Untouchables had discovered a ledger during a raid and using it as solid evidence.