In 1938 Marcello was arrested in New York for the sale of more of more than 23 pounds of illegal drugs, and served 10 months in prison. Afterwards he associated with Frank Costello, the leader of the Mafia in New York.
By the late 1940s, Marcello had taken control of Louisiana's gambling network and joined forces with Meyer Lansky to buy some of the biggest casinos in the New Orleans area, making him the undisputed leader of the New Orleans Mob. He was to hold this position for the next 30 years.
In March of 1959 Marcello appeared before the Senate Committe invesgating organized crime, facing Robert F. Kennedy as chief counsel to the committe and his brother, Senator John F. Kennedy, as a member of the committe. Marcello repeatedly invoked the fifth amendment, refusing to answer any questions relating to his background, activites, and associates.
After becoming president, JFK appointed his brother as U.S. Attorney General, and the two men started a war on organized crime. By the spring of 1961, the Attorney General had Marcello arrested and forcibly removed to Guatemala.
But it didn't take long for Marcello to return to the U.S., with vengeace in his heart. He swore that he would murder President Kennedy, and it is now known, based on long suppressed FBI reports, that Marcello confessed to ordering Kennedy`s assassination to a reliable FBI informant and said that long time suspect David Ferrie introduced him to Lee Harvey Oswald. This bombshell information was reported by both CNN and Fox News. Marcello's guilt was also confirmed by mafia attorney Frank Ragano and by HSCA director, G. Robert Blakey - even before they were aware of his confession.