James Colosimo, Italian-American mob boss (born 1878)

Vincenzo Colosimo, known as James "Big Jim" Colosimo or as "Diamond Jim", was an Italian-American Mafia crime boss who emigrated from Calabria, Italy, in 1895 and built a criminal empire in Chicago based on prostitution, gambling and racketeering. He gained power through petty crime and heading a chain of brothels. From 1902 until his death in 1920, he led a gang known after his death as the Chicago Outfit. Colosimo was assassinated on May 11, 1920, and no one was ever charged with his murder. Johnny Torrio, an enforcer whom Colosimo imported in 1909 from New York, seized control of Colosimo's businesses after his death. Al Capone, a close associate of Torrio, has been accused of involvement in Colosimo's murder but was not yet in Chicago at the time.

May 11 is the 131st day of the year in the Gregorian calendar; 234 days remain until the end of the year.