Though it's next to impossible to determine where a rumor begins, some of its history surfaces when it's promulgated by those in the public eye or in positions of influence. In 1991 Prof. Leonard Jeffries, chairman of [New York] City College's African-American studies department was loudly proclaiming this canard as fact. This wasn't the first time the controversial professor had made erroneous, racially-biased statements; in a speech earlier that same year, he proclaimed that Jews and the Mafia had teamed up with white conservatives to "destroy the Blacks" and announced it was well known that ''rich Jews'' were responsible for the Black slave trade.
http://www.snopes.com/history/american/liberty.htm