He accomplished legendary feats, even earning the appreciation of Theodore Roosevelt, of whom he was a great friend. At thirty, he was promoted detective, and entered the investigation section; in 1895 President Roosevelt personally made him a sergeant and in 1905 he was promoted to lieutenant, the first Italian agent to enter the Bureau; since then, he wore only dark suits, prince Albert style overcoats, with double sole shoes and bowler hat.
He took the command of the "Italian Branch", a group of five Italian agents (Maurice Benoil, Peter Dondero, George Silva, John Longomarsinie, Ugo Cassìdi), in his judgment necessary to fight the "Black Hand". In New York, between Manhattan and Brooklyn, lived around one million Italian immigrants, in the districts of Little Italy, East Harlem and Williamsburg.
He declared war to powerful Mafia bosses, responsible of 46% of all murders that were committed. He took actions that no policeman had ever been able to take, with adventurous, legendary actions, in his intelligent, determined style, without ever compromising on any level. His secret weapon was disguise, which allowed him to reach more closely into the complex world of the Mafia.