That was a hoax. They could never find any evidence that the person was an actual Klan member. He just called a newspaper and said he was in the Klan and has donated to Hillary Clinton's campaign. Was never corroborated.
"...the successful annihilation of organized crime's subculture in America would rock the 'legitimate' world's foundation, which would ultimately force fundamental social changes and redistributions of wealth and power in this country. Meyer Lansky's dream was to bond the two worlds together so that one could not survive without the other." - Dan E. Moldea
