After the brutal St. Valentine's Day Massacre, public opinion turned against Al Capone, and you will see how this was the beginning of the end for him. The media coverage of a violent, possibly mafia-related, killing shocked the American public. Although no evidence could be found linking Capone to the crime directly, many people assumed he was the mastermind. The media began to hound him, and President Hoover was determined to bring Capone down. Ultimately, it was tax evasion that would allow law enforcement to begin the hunt for America's most famous mob boss.