I found this on the FBI's website. I'm looking for more names.

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Giuseppe Esposito was the first known Sicilian Mafia member to emigrate to the U.S. He and six other Sicilians fled to New York after murdering the chancellor and a vice chancellor of a Sicilian province and 11 wealthy landowners. He was arrested in New Orleans in 1881 and extradited to Italy.

New Orleans was also the site of the first major Mafia incident in this country. On October 15, 1890, New Orleans Police Superintendent David Hennessey was murdered execution-style. Hundreds of Sicilians were arrested, and 19 were eventually indicted for the murder. An acquittal generated rumors of widespread bribery and intimidated witnesses. Outraged citizens of New Orleans organized a lynch mob and killed 11 of the 19 defendants. Two were hanged, nine were shot, and the remaining eight escaped.

The American Mafia has evolved over the years as various gangs assumed, and lost, dominance over the years—for example, the Black Hand gangs around 1900, the Five Points Gang in the 1910s and ‘20s in New York City, and Al Capone’s Syndicate in Chicago in the 1920s.