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

Texas businessman, George de Mohrenschildt was friends with Lee Oswald. He speaks many langauges ans travels extensively. As a result, he is often asked for information on the countries he has visited by the FBI. George recruits Lee to do the same based on his defection to Russia. He also tells Parmenter about Lee when Parmenter when he is looking for a pansy for his plot to attempt to assassinate President Kennedy.