Cosmano and other Black Handers, including James "The Mad Bomber" Belcastro, preyed on the residents of Chicago's Little Italy and other city neighborhoods at the turn of the 20th century.
In 1910, Cosmano tried to extort money out of James "Big Jim" Colosimo, a powerful brothel owner in the Levee section of Chicago.
To protect himself, Colosimo brought in his nephew Johnny "The Fox" Torrio, a New York mobster from the Five Points Gang.
After Torrio's arrival in Chicago, ten members of the Black Hand gang had been murdered.
Though defended by Clarence Darrow, both Murphy and Cosmano were convicted of conspiracy to rob the US Mail.