Complex sentence: The man, local leader of the "Indian Patrol", shot "Chief Melancon" in the head in full view of other tribesman, but wasn't prosecuted by local authorities and succeeded in stealing the land from the Tunica.
Split into simpler sentences: The man, a local leader of the "Indian Patrol", shot "Chief Melancon" in the head in full view of other tribesmen. He was not prosecuted by local authorities and succeeded in stealing the land from the Tunica.