Who is George de Mohrenschildt from Libra and what is their importance?

George de Mohrenschildt is a business man living in Dallas who befriends Lee Oswald. George knows many languages and travels extensively, often answering to the CIA with information on the countries he has gone to visit. George recruits Lee to do the same based on his defection to Russia. At the same time, George tells Parmenter about Lee when Parmenter needs someone to be a pansy for his plot to attempt to assassinate President Kennedy.