My GG grandfather fled France about 1848-1850 after he had killed a cousin in a duel. He was probably about 16-18 when it happened. I have his birthdate but he changed his name in America, and never revealed his French name. He claimed birth in New York all his life, but his daughters knew otherwise. It was rumored the cousin may have been connected to the French royal family. I've always thought if the cousin could be identified, perhaps authorities would have records of his suspected slayer. Anyone have any ideas?